Add strike, aligned text, and let indents go up to 20 times.
Add logo back in for commit.
Allow arbitrarily deep indents.
Tweak some of Guy's changes / undo some changes he reverted.
Fix html parsing for left/center/right-aligned text.
Add HTML generation / parsing support for todo lists.
Add html export support for aligned text.  Improve whitespace handling when importing/exporting html.