Use mateweather also for GTK3
mate-panel: Add GTK3 support
libmate-panel-applet: Add GTK3 support
fish: Add GTK3 support
clock: Add GTK3 support
notification_area: Add GTK3 support
wncklet: Add GTK3 support
Bump version to 1.7.0
Merge pull request #131 from infirit/master

Remove autogenerated files
Fix gtkx.h include for GTK2
Possible fix for gtk2 build error. Bring back some code.