adding a currentType method to get current source type if known
setSource method tweaks
removing redundant ready check
using vjs.bind
Merge branch 'source-type' of github.com:guardian/video.js into guardian-source-type

Conflicts:
	src/js/exports.js
Moved source list handling out of src() and into its own function to simplify src
Merge pull request #1 from heff/guardian-source-type

Guardian source type
Merge branch 'source-type' of github.com:guardian/video.js into guardian-source-type
Added docs and changelog line for #1320