- Removes 'span' from being a valid part of alignment formats so it's
not used to align contents, since it's going to mostly be an inline
format, wheras you'd really want alignment on the parent block.
- Adds direction cleaning to all direction change events, to remove
direction styles and child direction controls which may complicate
matters and cause direction changes not to show.
- Makes text direction controls work with table cell range selections,
which TinyMCE does not consider by default, via manual handling.
For #4843
Required a lot of working around TinyMCE since it added a
preview/wrapper element in the editor which complicates things.
Added view new "fixes.js" file so large hacks to default TinyMCe
functionality are kept in one place.
