Move the ruby anonymous box logic back to its original place

This was moved in commit 3d05e2e05c72b01404cf290bf07c7f0f367827a7
but seems to belong better in its original place since it creates
boxes and does not merely set properties.
Remove the region nullification from the parser

Scripts can already get cues into the state that this tries to avoid,
and it seems harmless due to how the rendering algorithm works.

https://www.w3.org/Bugs/Public/show_bug.cgi?id=25948
Merge pull request #88 from foolip/rm-region-null

Remove the region nullification from the parser
Merge pull request #85 from foolip/move-ruby

Move the ruby anonymous box logic back to its original place
Merge commit 'f0d4c6855f0facf9b75f8369c7e43c94e9028e2f' into revert-regions
Merge commit '07496d39fed22a4fcc81bc0ebd547b14956f933b' into revert-regions

Conflicts:
	webvtt.html