Only build one copy of qtile for all architectures

Hooray python :-)
Fix #282: focus on next window on kill in TreeTab
Update test documentation
Xmonad layout works with relative secondary sizes

...to properly handle different screen sizes.

Closes #287
java focus workaround

workaround for #227
Closes #227
Closes #289

@tych0: rearranged some code
Added more info formats, and fixed a bug in one
Fixed the clumsy handling of %% in format strings.
Much nicer do_format