Build: Remove CoffeeScript tasks

- This does not affect the Gruntfile.coffe since that is provided by
Grunt itself
Mediaplyer: Port back from CoffeeScript

- Several TODOs and FIXMEs to address
Standardize naming to multimedia
Fixed the naming and documented the time functions
Fixed and documented the parse functions
Fixed and documented the captions loading and display functions
Added event documentations
Documented the playerApi
Fixed JSHint and SASS include issues
Merge pull request #3262 from nschonni/v4-convert-mediaplayer-coffee

[WIP] V4 convert mediaplayer coffee