build should not fail if html and js files are same name (for issue #90)

Per the comments in #90, partials should not overwrite similarly-named JS files during build. This implements gulp-ng-templates and places the result in .tmp, which gets collected into the app.js.

Please let me know if this needs changes for merge as we've run into this issue a few times when using the angular style guide with this generator.

Thanks for the great generator!