Example old log line:
```
2019-01-18T14:28:20.750-0800 [TRACE] client.alloc_runner.task_runner: running poststart hooks: alloc_id=...
```

Example new log line:
```
2019-01-18T14:23:54.381-0800 [TRACE] client.runner: running poststart hooks: alloc_id=...
```

TaskRunner log lines can be differentiated from AllocRunner log lines by
the presence of a `task=...` field.

client: restore Terminated event on every exit

Fix typo in PluginLoader

Some Windows fixes and CI

Fix one more place that should be using taskResources

taskResources handles new resource fields in a backwards compatible way

v0.9.0-dev started emitting a Terminated event every time a task process
exited. While this wasn't true in previous versions, it's a useful task
event because it's the only place for job operators to view the task's
exit code.

This behavior is asserted in the e2e/taskevents tests.

Co-Authored-By: dantoml <dani@tomlinson.io>

Co-Authored-By: dantoml <dani@tomlinson.io>

Co-Authored-By: dantoml <dani@tomlinson.io>

Due to https://github.com/tsenart/deadcode/issues/3 we can't specify
these consts on their own. This moves them into the _platform_test.go
files to avoid creating a package that only exposes a couple of values.

* Docker for Windows does not support ulimits
* Use filepath.ToSlash to test workdir
* Convert expected mount paths to system style
* Skip security-opt test on windows
  - Windows does not support seccomp, and it's unclear which options are
    available.
* Skip StartN due to lack of sigint
* docker: Use api to get image info on windows
* No bridge on windows
* Stop hardcoding /bin/

Uses the home directory and windows path expansion, as c:\tmp doesn't
necessarily exist, and mktemp would involve unnecessarily complicating
the commands.

This validates the slash variant of a RelativeDest, rather than the
platform native version, to support test execution on windows.