Move next/prevgroup, add togglegroup
update unit tests

grouptoggle -> togglegroup
whitespace fixes
When deleting a group, switch to previous group

...insted of the previous configured group.

Closes #304
Fix unit test
patch for iss300

Change the window's layout level behavior
When focusing on a window, bring it to front.
Floating(but not maximized or fullscreened) windows always on top.

Closes #300
Closes #302
Merge https://github.com/qtile/qtile into develop