texture-tower: Remove CPU codepath for mipmap generation

The CPU codepath for mipmapping is unusably slow, and we expect modern
graphics cards with modern TFP/FBO support.
tower: make sure not to blend when updating tower

Each level in the tower is initialized by binding the texture for that
level to an offscreen framebuffer and rendering the previous level as a
textured rectangle. The problem was that we were blending the previous
level with undefined data so argb32 windows with transparencies would
result in artefacts. This makes sure to disable blending when drawing
the textured rectangle.
tower: Fix erroneous return value

The function's return value is void, not gboolean.
monitor-config: prevent assert that at least one output is connected

Apparently some connector technologies don't distinguish between
on and off, and there might be valid use cases for running without
any connected monitor.
In that case, just avoid any configuration at all.

https://bugzilla.gnome.org/show_bug.cgi?id=709009
MonitorManager: make sure to pass the right sizes to vararg functions

A gulong is not enough to get 64 bits in all arches, so we must
cast it, or we can corrupt the stack.

This was downstream bug bugzilla.redhat.com/show_bug.cgi?id=1002055

https://bugzilla.gnome.org/show_bug.cgi?id=707267
xrandr: Use specified output property name for backlight control

Backlight controls are set using the "BACKLIGHT" XRANDR output property.
This should be "Backlight" according to the XRANDR spec [1].

Some drivers (Intel) export both properties and some only the specified property (nvidia).
Users of drivers that only export the specified property cannot change their backlight using XRANDR.

[1] http://cgit.freedesktop.org/xorg/proto/randrproto/tree/randrproto.txt section 9.1

https://bugzilla.gnome.org/show_bug.cgi?id=723606
MonitorXrandr: Mask a BadValue error on VirtualBox.

https://bugzilla.gnome.org/show_bug.cgi?id=707563
screen: Name the guard window

So that extensons can recognize it, for the case where they
want to watch the window list.

https://bugzilla.gnome.org/show_bug.cgi?id=710346
window-props.c: React to changes to _GTK_FRAME_EXTENTS

When _GTK_FRAME_EXTENTS changes, we need to redo constraints on
the window - this matters in particular if the toolkit removes
invisible borders when a window is maximized, since otherwise
the maximized window will be positioned as if it still has
invisible borders.

https://bugzilla.gnome.org/show_bug.cgi?id=714707
build: Create m4 directory

Due to changes in gnome-common git, an implicit m4 directory is no
longer created during autogen. The attached patch explicitly and
correctly specifies a macro directory.

https://bugzilla.gnome.org/show_bug.cgi?id=706787
Update .gitignore
ui: Disable scaling support in Gtk+

We can't really support the Gtk+ automatic scaling, as to much
code relies on the GdkWindow and XWindow sizes, etc to match.
In order to keep working we just disable the scaling, meaning
we will pick up the larger fonts, but nothing else. Its not
ideal but it works for now.

https://bugzilla.gnome.org/show_bug.cgi?id=706388
window: Make sure to end the grab even if the last action was a snap

This seems to be a cherry-pick failure while we were switching event
handling around. This matches what the master branch does.