utils.getFileContent is now async
Merge pull request #1 from stasm/async-getFileContent

Rewrite utils.getFileContent to be async. r=gandalf
Support better program args model and dir-2-dir diff
plain dir-2-dir comparison
Speed up by lazy loading jsdom
Get the output to look more like pike's compare-locales'
split getLangpackFromDir and getLangpackFromPaths
move part of the bin to lib
make sure we support l20n files
remove empty file app.js
Update to singleton PropertiesParser
cleanup after last patch
update l20n parser to new AST
Fix lint errors and tests
bin/cli.js
Make manifest, resources and langpacks async
Use getManifest, getResources, getLangpacks
tests for all 4 modes
Fix compare dirs
Add JSON serializer