2.5: Text edit mode operators back. Took me a while getting

2.5: Text edit mode operators back. Took me a while getting
them nicely repeatable, and splitting up the big edit_text
operator into individual operator so it's all nicely scriptable,
documented, configurable, etc..

* Insert Text, Line Break, Insert Lorem
* Toggle Case, Set Case, Toggle Style, Set Style, Set Material
* Copy Text, Cut Text, Paste Text, Paste File, Paste Buffer
* Move, Move Select, Delete
* Change Spacing, Change Character

Notes

* Text (datablock) to Object doesn't work yet, will need to
  implement text editor context for that.
* Some shortcut keys don't work because screen/wm overrides them,
  ctrl+x, ctrl+left/right. That override goes top down which works
  well for some cases, but here we need to override in the other
  direction.
* There's no unicode support in RNA, or the user interface code
  for that matter, but text strings can contain these characters.
  At the moment it stores a UTF-8 string in char arrays, which is
  supposed to be nicely compatible with ascii. Seems reasonable to
  add support for UTF-8 in the interface code, python bindings, ..
  eventually?