prepare modules for concatenating
prepare modules for concatenating (2)
remove index files

since the modules’ class files will be listed in JSON files
`shapes` module: added dependencies
fixed a bug in the `util` module
removed `gulpfile.js`

Gulp natively executes CoffeeScript Gulpfiles.
rewritten `gulpfile.coffee`

- code split into more tasks (`lint`, `concat`, `build`, `minify`,
`cleanup`)
- module get concatenated first -> less CoffeeScript utility headers ->
smaller distribution file size
- new `default` Gulp task
rebuild `/dist` files
Merge branch 'module-concat-files' into coffeescript-rewrite