Update to support more regions

Relates https://github.com/hashicorp/terraform/issues/524
Added `eu-central-1`, `cn-north-1` and `us-gove-west-1`(hi NSA)
I checked `goamz`, @mitchellh already has added support for those regions
Do not read temporary editor files, fixes #548

This fixes a bug where Terraform would error with the following:

```
Error loading config: Error reading
/Users/rhenrichs/work/example/.#example.tf: open
/Users/rhenrichs/work/example/.#example.tf: no such file or directory
```

The solution implemented here ignores the common emacs and vim
temporary file formats.

Note: the potential danger with merging this is that Terraform could
quickly have requests to ignore other file formats.
core: refactoring the way sets work internally v2

This is a refactored solution for PR #616. Functionally this is still
the same change, but it’s implemented a lot cleaner with less code and
less changes to existing parts of TF.
Fix for #664, crashed due to ig.Attachements being 0
Usage info for graph command was actually that of output
Setting the VPC id to blank for unattached igws
Merge pull request #666 from donjohnson/patch-1

Usage info for graph command was actually that of output
Merge pull request #665 from gosuri/master

Fix for #664, crashed due to ig.Attachements being 0
Heroku SSL certificate support added
Heroku SSL support: fixes after code review of @svanharmelen
Making all function names consistent

Before all providers were using the helper.Schema approach the helper
function had these names. Now they all use names consistent with the Go
naming conventions except for these last few…
Merge pull request #674 from svanharmelen/f-make-func-names-consistent

Making all function names consistent
Merge pull request #672 from plan3-labs/heroku_cert_support

Heroku SSL certificate support
website: Add link to heroku_cert in the docs
Merge pull request #663 from svanharmelen/f-fix/change-set-logic

core: refactoring the way sets work internally v2
Fixed a type and reordered the case statements

Making in more inline with the existing code…
Merge pull request #675 from svanharmelen/f-fix-typo/style

Fixed a type and reordered the case statements
Looking at issue #639 this seems to be the root cause

After fixing this part, there also needs to be made a change to the
example given or the schema of aws_elb.
Merge pull request #632 from KushalP/master

config: do not read temporary editor files, fixes #548
update CHANGELOG