Fix periodic job state

Proper reference counting through task restarts

Mention Nomad CLI remote usage

Fix TLS use in AllocFS API and region/dc detection

Added information about `NOMAD_ADDR` environment variable for Nomad CLI remote usage.

Remove incorrect list of supported protocols

added git docs to artifacts

Fix typo in documentation link

This PR fixes an issue in which a periodic job would incorrectly
transistion to status dead.

Fixes https://github.com/hashicorp/nomad/issues/2268

Remove the reference to `http://localhost:4567` within the Rolling Update
strategy documentation and fix the link to the `nomad plan` command
documentation.

Wrong shell variable used when changing directory

This PR fixes an issue in which the reference count on a Docker image
would become inflated through task restarts.

The correct list is like 5 lines up

Fix panic when restarting non-running task

This PR fixes an issue that is hit when running templates with restart
mode in which the client could panic when the handle is not running.

Fixes https://github.com/hashicorp/nomad/issues/2479

Updated logo in README.md

The logo file has been moved with [d9640776](https://github.com/hashicorp/nomad/commit/d96407769a4a33901b5de66b7053e08574428698) by @sethvargo. Hence the logo reference in the README.md is broken. This PR fixes that.

Fix diff alignment and remove no change DC

Old Output:
```
+/- Job: "example"
    Datacenters {
  Datacenters: "dc1"
}
+/- Task Group: "cache" (1 create/destroy update)
  +/- RestartPolicy {
    +/- Attempts: "10" => "9"
        Delay:    "25000000000"
        Interval: "300000000000"
        Mode:     "delay"
  }
  +/- EphemeralDisk {
        Migrate: "false"
    +/- SizeMB:  "300" => "301"
        Sticky:  "false"
  }
  +/- Task: "redis" (forces create/destroy update)
    +   Meta[key]: "value"
    +/- Config {
          image:           "redis:3.2"
      +/- port_map[0][db]: "6379" => "6380"
    }
    +/- Resources {
          CPU:      "500"
          DiskMB:   "0"
          IOPS:     "0"
      +/- MemoryMB: "256" => "257"
    }
    +/- Service {
          Name:      "global-redis-check"
          PortLabel: "db"
      +/- Check {
            Command:       ""
            InitialStatus: ""
            Interval:      "10000000000"
            Name:          "alive"
            Path:          ""
            PortLabel:     ""
            Protocol:      ""
        +/- Timeout:       "2000000000" => "3000000000"
            Type:          "tcp"
      }
    }
```

New Output:
```
+/- Job: "example"
+/- Task Group: "cache" (1 create/destroy update)
  +/- RestartPolicy {
    +/- Attempts: "10" => "9"
        Delay:    "25000000000"
        Interval: "300000000000"
        Mode:     "delay"
      }
  +/- EphemeralDisk {
        Migrate: "false"
    +/- SizeMB:  "300" => "301"
        Sticky:  "false"
      }
  +/- Task: "redis" (forces create/destroy update)
    +   Meta[key]: "value"
    +/- Config {
          image:           "redis:3.2"
      +/- port_map[0][db]: "6379" => "6380"
        }
    +/- Resources {
          CPU:      "500"
          DiskMB:   "0"
          IOPS:     "0"
      +/- MemoryMB: "256" => "257"
        }
    +/- Service {
          Name:      "global-redis-check"
          PortLabel: "db"
      +/- Check {
            Command:       ""
            InitialStatus: ""
            Interval:      "10000000000"
            Name:          "alive"
            Path:          ""
            PortLabel:     ""
            Protocol:      ""
        +/- Timeout:       "2000000000" => "3000000000"
            Type:          "tcp"
          }
        }
```

Old Output:

```
+/- Job: "example"
    Datacenters {
  Datacenters: "dc1"
}
+/- Task Group: "cache" (1 create/destroy update)
  +/- RestartPolicy {
    +/- Attempts: "10" => "9"
        Delay:    "25000000000"
        Interval: "300000000000"
        Mode:     "delay"
  }
  +/- EphemeralDisk {
        Migrate: "false"
    +/- SizeMB:  "300" => "301"
        Sticky:  "false"
  }
  +/- Task: "redis" (forces create/destroy update)
    +   Meta[key]: "value"
    +/- Config {
          image:           "redis:3.2"
      +/- port_map[0][db]: "6379" => "6380"
    }
    +/- Resources {
          CPU:      "500"
          DiskMB:   "0"
          IOPS:     "0"
      +/- MemoryMB: "256" => "257"
    }
    +/- Service {
          Name:      "global-redis-check"
          PortLabel: "db"
      +/- Check {
            Command:       ""
            InitialStatus: ""
            Interval:      "10000000000"
            Name:          "alive"
            Path:          ""
            PortLabel:     ""
            Protocol:      ""
        +/- Timeout:       "2000000000" => "3000000000"
            Type:          "tcp"
      }
    }
```

New Output:

```
+/- Job: "example"
+/- Task Group: "cache" (1 create/destroy update)
  +/- RestartPolicy {
    +/- Attempts: "10" => "9"
        Delay:    "25000000000"
        Interval: "300000000000"
        Mode:     "delay"
      }
  +/- EphemeralDisk {
        Migrate: "false"
    +/- SizeMB:  "300" => "301"
        Sticky:  "false"
      }
  +/- Task: "redis" (forces create/destroy update)
    +   Meta[key]: "value"
    +/- Config {
          image:           "redis:3.2"
      +/- port_map[0][db]: "6379" => "6380"
        }
    +/- Resources {
          CPU:      "500"
          DiskMB:   "0"
          IOPS:     "0"
      +/- MemoryMB: "256" => "257"
        }
    +/- Service {
          Name:      "global-redis-check"
          PortLabel: "db"
      +/- Check {
            Command:       ""
            InitialStatus: ""
            Interval:      "10000000000"
            Name:          "alive"
            Path:          ""
            PortLabel:     ""
            Protocol:      ""
        +/- Timeout:       "2000000000" => "3000000000"
            Type:          "tcp"
          }
        }
```

Mention 0.5.5 tool incompat with 0.5.4 agents