Fix bladelayout neighbours
Make halflayout neighbours more consistent

Previously, it was possible to go down from tile 0 to tile 1, but not up
from 1 to 0.

Now, don't allow going down from tile 0 (as it's not actually down).
Improve tabGroups support

This also introduces a proper method to add clients to a tile and remove
clients from it which
allows us to do sanity checking
Nip some potential errors in the bud

This includes error checking and initializing variables to proper values
When no window is selected, just use the first one

This only applies to the focus hotkeys
Release v1.1.4