Register select all as a command and perform programmatically

This fixes the following issues:
* Not working when a focusable node selected
* Not working when a table selected, now selects
  the entire table
* Sometimes not working when a table cell is being edited
* Potential to have a select all tool
* Generally being less at the whim of content editable

It does not fix the ce-false-first-or-last-child issue in Chrome.

Change-Id: Ica731c596af9e6e3495298105ef1e79ba5cccd63
Merge "Register select all as a command and perform programmatically"