Remove space at end of blocks that format.py will merge

Otherwise they will end up as "<p>foo bar. </p>"
Merge pull request #52 from foolip/rm-merge-space

Remove space at end of blocks that format.py will merge
Make it clear where the Cue settings for region cues are applied.

Since region cues don't have the following settings:
* vertical
* size
* line
most of the "Apply WebVTT Cue Settings" part is not applicable.
Clarify region scrolling approach.

Closes https://www.w3.org/Bugs/Public/show_bug.cgi?id=22114
Merge pull request #53 from silviapfeiffer/cue_settings

Make it clear where the Cue settings for region cues are applied.