Clean up plugin logic and warning text

added a test
Conflicts:
	CHANGELOG.md
	lib/language_pack/rails2.rb
	lib/language_pack/rails4.rb
	spec/rails3_spec.rb
Bugfix and More tests for plugin logic
Conflicts:
	spec/rails3_spec.rb
	spec/rails4_spec.rb
Revert "Merge pull request #132 from heroku/schneems/less-inheritance-in-plugins"

This reverts commit 968736e977fcb54705d2fe2a95f11f2192026d17, reversing
changes made to 34f5f706158d55fbeabc548c5fbd0f851e547fd6.

Still some issues with this Pull Request. Going to work on it some more.

Conflicts:
	spec/rails3_spec.rb
	spec/rails4_spec.rb
remove extra '--' from warnings
should set $GEM_PATH as well for the build process

if this isn't setup properly, locally it might pick the wrong bundler
Bugfix and More tests for plugin logic

Actually testing for presence of directories now !
Conflicts:
	spec/rails3_spec.rb
	spec/rails4_spec.rb
	spec/spec_helper.rb
rails 4 plugin work

* move rails_12factor gem test to the beginning
* test against ruby 2 since that's the new default
* rails_12factor not rails_12_factor

Conflicts:
	spec/rails4_spec.rb
rails 3 plugin work

* gem and plugin names are different
* rails_12factor not rails_12_factor

Conflicts:
	hatchet.json
	spec/rails3_spec.rb
only warn once about plugin injection in rails 3
use `PluginInstaller` for runtime asset compilation

Conflicts:
	lib/language_pack/rails3.rb
set deprecation notices for runtime assets compilation

Conflicts:
	lib/language_pack/base.rb
Symlink ruby.exe to ruby

Rails 4 introduced the `bin/` directory to generated projects with executables `rails`, `bundle`, `rake`, etc. The file generated on windows has a link to an incorrect `ruby.exe` in the shebang line. See #134.

This PR adds a symlink so that `ruby.exe` can be called in addition to `ruby.
Conflicts:
	Gemfile.lock
	hatchet.json
	spec/rails4_spec.rb