Snapshot Time again

[micheus]

In order to inform the main developers in what I'm working on I'll put here the bug fixes for this snapshot that I'm going to push on github.

a) Unhide all objects in UV window not working - fixed
-> added the absent call to wings_shape:show_all/1
b) Certain shotcuts changes are not saveable? - fixed.
-> default hotkeys for a command is removed from hotkey list if there is a user defined for it
c) File dialogs (Save As, Open, etc) with kb shortcuts continues to pop up again forever - Not present in the latest Master branch
-> nothing to done here.
d) Unhide adjacent faces were crashing when object has other than default material applied to it - fixed
-> added call to gb_sets:to_list() before process faces list
e) Fixed an issue related to dynamic dialogs (for coders)
f) Fixes to "Image Plane" preview dialog

Already pushed to github:
a) Crash related to "saved views" and "Selection Groups" windows...
b) Fixes for POV-Ray pluging related to light exporting