gtk3: set rgba visual for applets
clock: Dont use deprecated rsvg_pixbuf_from_file_at_size

This required to copy some code from GTK3 source to make it working with GTK2 too

Thanks to Sander Sweers for the help to replace rsvg_pixbuf_from_file_at_size
Merge pull request #195 from dnk/applet_rgba_visual

gtk3: set rgba visual for applets
Replace opacity key to alpha value in color key.
Fix expanded panels and size allocation
Fix RGBA issues for GTK3
Merge pull request #209 from rilian-la-te/fix_rgba_all

Fix rgba all
Merge pull request #211 from rilian-la-te/remove_opacity_key_gtk3

Remove opacity key gtk3
Merge pull request #212 from rilian-la-te/fix_expand

Fix expand
Restore way to close windows with middle click

It was forgot during transition to libwnck
Closes https://github.com/mate-desktop/mate-panel/issues/191
Use MateColorButton in panel properties dialog
Bump required mate-desktop version to 1.9.2

Needed for the new MateColorSelecionDialog.
Bump required mate-desktop version to 1.9.1
Bump version to 1.9.1
Fix warning, include gdkx.h also for Gtk+ 2
Remove unused variable
Remove gdkkeysyms-compat and update keys
Replace GtkObject with GObject also for Gtk+ 2
GtkAllocation cleanup