Started redesigning the box positioning mechanism.
This patch introduces an example and a work-over of the data model.
Syntax and Parser to come.
Oops, fix the example to actually use the correct align values.
Add link to previous draft.
Tidy up references to WHATWG spec a bit.
Bring back a SOTD section, because ReSpec requires it.
Specify syntax for "WebVTT line position cue setting".
Also rename "cue position alignment" to "text position alignment" to
stay in sync with the "text position" cue setting.
Specify text position alignment syntax.
Set default values for cue settings in parsing.
Fix up parsing of line setting.
Finish the parsing part for the text position/align cue setting.
Fix up browser VTTCue API with new cue setting alignment values for the cue box (line and text position).
Fix up the text position alignment logic for bidi text.
Fix up the line alignment logic for vertical text.
Add default text position setting determination for non-middle aligned cue text in parsing section.
Merge commit '86ba250eaf7d2e53f614d684755ef13d089c7652' into revert-regions

Conflicts:
	webvtt.html
Merge commit 'b43524375d7575e950474fec05ac1ad9d0573ead' into revert-regions
Merge commit 'fd94ba5c29fe4951ced71a528212eab62ecc5f43' into revert-regions

Conflicts:
	webvtt.html
Merge commit 'd4db04ae0aa6c23433be290b2bdb677b989d575f' into revert-regions
Merge commit 'f98fddacaba6f66053bc14d560a99a4c518785ae' into revert-regions

Conflicts:
	webvtt.html
Merge commit '1fdced7d6792f30d18a33b8ed62bea7283490e93' into revert-regions
Merge commit 'aa6ea9b2870d40d3f4dd668309597354f48e8c68' into revert-regions

Conflicts:
	webvtt.html