Added "reset --hard" feature.

Added `reset --hard` feature and a preference to enable dangerous features in brackets-git.
Edited according to 328
fix errors
Merge pull request #328 from FezVrasta#hardReset
Add checkout button.
Add reset buttons.
Delete the legacy template folder.
Add refresh callback.
Make gitReset support reset to a specific commit.
Add reset function.
Change to new modular Git interface.
Update NLS info.
Update NLS.
Add 'advance mode' options in preferences dialog.
Change ADVANCE_MODE to ADVANCED_MODE.
rewriting pr
Merge pull request #316 from yfwz100#checkout
Changelog for 0.13.0