Made a few <br>s self-closing.
Corrected examples and testcases.
Updated development.html to HTML5 (contenteditable needs that).
What’s in a name?
Changed &nbsp; into XHTML-friendly &#160;
Fullscreen button had no tooltip
Fixed failing FF test caused by bad browser version string comparison.
Added a #346 update note and added Philipp Cordes to authors.
Merge pull request #383 from wymeditor/issue_346

Tweaks to #346 XHTML bugs