Add accessors for Media Fragments URI #18
Description
The Media Fragments URI Specification defines how dimensions (spatial, temporal, track, …) can be specified. <img src="foo.png#xywh=10,20,100,40"> would specify to show a cropped version of the actual image (100x40 pixels at a 10x20 pixel offset). <audio src="/audio.ogg#t=5,20"> wouls specify to play the audio file from 5th second till 20th second.
URI('foo.png#xywh=10,20,100,40').mediaFragment() could return {x: 10, y: 20, w:100, height:40}, while URI('foo.png').mediaFragment({y: 20, w:100, x: 10, height:40}) could lead to foo.png#xywh=10,20,100,40.
Things get more interesting with converting different representations of the same information, as the Temporal Dimension notation shows.