Ticket #134 #223 - Added focus() method which does the dirty work of getting
focus to work across browsers. This also fixes the problem with IE9/10 where
the shortcuts only worked the first time and you had to click into the editor
to get them to work again.

To do: docs and tests
Ticket #134 #223 - Added docs for focus() method.
Ticket #134 #223 - Removed focus and blur events from the docs. Adding that as
another ticket for 0.3.0
Ticket #134 #223 - Now the focus() method is working across browsers. Removed
is() support since it was turning out to be too much work. It's now it's own
ticket (#229).

This fixes the IE9/10 issue where the editor was not focused so you could
keep typing after switching over to the preview() (through clicking the icons
or doing a key command).
Merge branch 'develop' of github.com:OscarGodson/EpicEditor into develop