Optimized all PNGs
Simplified the app.yaml file and fixed some mistakes
Refactoring the build process
Merge pull request #1026 from wibblymat/app-yaml

Simplified the app.yaml file and fixed some mistakes
Merge pull request #1028 from wibblymat/images

Optimized all PNGs
Merge pull request #1027 from wibblymat/tidying

Refactoring the build process
Update documentation

Commit bad4a21 moved the Gruntfile from `src` to the root folder,
therefore `npm install` should be run there.
Merge pull request #1029 from jacquerie/tidying-doc

Update documentation