Support mustache.erb and .module.js.erb

Relax the regex that checks for .mustache extension to not require end of string, because this fails with templates that end in mustache.erb for erb pre-processing.
Added tests to cover this case, also for module.js.erb. Erb processing may be needed to asset_path expansions for the asset pipeline.
Moved the JS test fixture files into a subdirectory for better clarity of tests vs fixture data. All tests pass.
Bump version to 0.2.0.0.2 and updated README.