Move xlib:allow-events after our event processing

So we could handle click anywhere and wouldn't conflict with
client. Client will only receive pointer event after we ungrab the
pointer.
Support move & resize floating window with s-mouse-{1,3}
Guess removed head by frame number. Fixes #71

SCALE-SCREEN tried to guess what head was removed by comparing their
screen position. If the removed head was positioned left or above other
heads, the other heads were moved to the left or up before SCALE-SCREEN
is ever called. This resulted in SCALE-SCREEN guessing wrong at what
head was removed.

Frame numbers of heads haven't (yet) been reassigned when SCALE-SCREEN
is called, so compare those instead.
Fix the version number in stumpwm.asd, fixes #103
Merge pull request #106 from jorams/fix-asd-release

Fix the version number in stumpwm.asd, fixes #103
Merge pull request #105 from jorams/xrandr-unhandled-error

Guess removed head by frame number. Fixes #71
Merge pull request #101 from kanru/float-move-resize-with-meta-cursor

Support move & resize with s-mouse-{1,3}
Also use group top-maps in SYNC-KEYS, fixes #87

Because SYNC-KEYS passed a window's screen to XWIN-GRAB-KEYS, the
bindings in the top maps of groups were ignored.
Merge pull request #109 from jorams/group-top-maps

Also use group top-maps in SYNC-KEYS, fixes #87
Support multiple X selection types

Generalize the selection handling system, adding the ability to get and
set the clipboard selection instead of just the primary selection. The
changes also open up the ability to use the secondary selection, but
that one is pretty much never used.

Note that this changes the functionality of the exported
symbol *X-SELECTION* by turning it into a property list.
Clean up selection support
Use the same gravity calculation everywhere

This also enables the use of :top, :bottom, :left and :right gravity for
the message and input window.
Merge pull request #112 from jorams/clipboard-selection

Support multiple X selection types
Merge pull request #113 from jorams/unify-gravity

Use the same gravity calculation everywhere
Make highlighting in the mode line configurable
Merge pull request #114 from jorams/mode-line-highlight

Make highlighting in the mode line configurable
Floating group: base current head on window

Instead of always returning the first head on the screen as the current
one, it makes more sense to instead return the head on which the current
window resides.
Merge pull request #115 from jorams/floating-current-head-by-window

Floating group: base current head on window
Take config from ~/.config/stumpwm/config after .stumpwmrc