Improvements to speed feature:

	- No longer requires an extra SVG for button
	- Speeds can be configured as an option to the player: use speeds: [list]

Add speed feature to Gruntfile.js
Remove speed SVG from Builder.py
Revert changes to /build/*
fix jshint problems and spelling
Change vtt track parser:
	- Lines no longer need to begin with a number. The information http://dev.w3.org/html5/webvtt/ indicates that each cue must have a timestamp and text; the chapter marker is optional
	- Add the now-optional chapter marker as a class on each cue when it is displayed, if one is specified
	- Add white-space: pre-wrap to the cue's css so the line breaks are honored
Alter timestamp regex so that timestamps to make the hours optional.
Merge branch 'master' of https://github.com/matthillman/mediaelement into matthillman-master

Conflicts:
	src/js/mep-feature-tracks.js