enhanced SceneToolBar tool handling (remove and insert at specific point)
Fix INT_MIN trade exploit (Fixes #2096)
added ModeButton specialisation of PushButton for use in SceneToolMode
Fix button graphics preventing mouse clicks (Fixes #2104)
allow externally supplied ModeButtons in SceneToolMode
Make MODL subrecord for light records optional (Fixes #2114)
renamed getElementMask to getVisibilityMask
Added proper slow fall effect mechanics.
updated credits file
Merge branch 'master' of https://github.com/OpenMW/openmw
added edit mode button to scene toolbar
Fix for issue #2051.  Not perfect (can get into a lock in some situations) but usable.
added edit modes for exteriors
Merge branch 'mode'

Conflicts:
	apps/opencs/view/render/pagedworldspacewidget.cpp
	apps/opencs/view/render/worldspacewidget.cpp
	apps/opencs/view/render/worldspacewidget.hpp
use placeholder icons in OpenCS when no proper icon is available