* Drop Go 1.5 compatibility env vars
 * Drop `make updatedeps` from `Makefile` and docs
 * Update README w/ vendored dep instructions

386 architecture builds were failing with:

```
builtin/providers/aws/resource_aws_sns_topic_subscription.go:216: constant 60000000000 overflows int
```

terraform: don't prune resource if count has interpolations

```
go tool vet -all .
builtin/providers/aws/resource_aws_elasticache_security_group.go:130: arg apierr.Code in printf call is a function value, not a function call
builtin/providers/aws/resource_aws_elasticache_subnet_group.go:155: arg apierr.Code in printf call is a function value, not a function call
```

config: Add new interpolation function - md5

aws_cloudwatch_metric_alarm docs reference 'namespace' twice.

Fix -module-depth typo

The module depth parameter had an equal sign instead of a dash in the name.

Remove `make updatedeps` from README steps

As of 0.6.11 `make updatedeps` has been replaced with vendored packages

https://github.com/hashicorp/terraform/issues/4960#issuecomment-178932434

Use four-space indent to catch `<pre>` formatting on GitHub for users
who copy/paste.

core: output "diffs didn't match" error details

Build with Go 1.6

Previously these details were relegated to the debug logs, which forces
the user to reproduce the error condition and then go digging for the
error message. Since we're asking users to report this error, let's give
them all the details they need right up front to make it a little easier
on them.

 * Mention requiring Go 1.6+ in the README in preparation for a follow
   up PR which updates our docs / Makefile to align with our vendored
   dependencies.

core: error instead of panic on self var in wrong scope

Fixes #4808
Fixes #5174

provider/aws: Enable DynamoDB Table to output `stream_arm` when streams are enabled

provider/aws: Implement RetentionPeriod Changes for Kinesis Stream

terraform: upgrade resource name regexp failure to error