Rework template/file loading to not require the default/ and to accept an array for explicit search path manipulation. This is the backwards compatible solution to migrate away from the implicit search path in favor of making it explicit when needed (which is rarely).
Conflicts:
	lib/chef/cookbook_version.rb
Tests for new loader behavior.
Conflicts:
	spec/unit/cookbook_version_spec.rb
Fix up the tests post-merge.
More unit tests to catch the negative case.
Add clarifying comment.
More comment-y goodness.
Merge pull request #2165 from coderanger/rfc017

RFC 17 implementation