Phase out old typewriter mode implementatin for ST3
Rough-and-ready implementation using on_text_command (ST3 only)

- Pythonesque implementation of Typing Mode
- Disable mouse clicks & drags in Scrolling Mode

Suggested by [bizoo](https://github.com/bizoo) at the [ST Forum](http://www.sublimetext.com/forum/viewtopic.php?f=5&t=13012&sid=9e72fb150b1d2847509a034f468170bd&start=10#p54139)
Remove keybindings for ST2 typing mode
Add Typing mode command

This allows the cursor to be properly positioned at EOF
Update auxiliary files
Correct loop
Remove legacy option
Update README
Remove main entries

I couldn't make the typing mode to update the checkbox in the menu,
so I decided to remove them altogether. Kind of drastic, but then
again, who uses the menu? ;)