Merged Visual mode and GZDoom Visual mode into GZDB Visual mode. GZDoomEditing.dll is no longer required.

Added UDMF Controls plugin.
Added "Snap selected vertices to grid" mode (Found in Edit menu).

Doom-style walls shading is now applied in Visual Mode

@ more fixes for auto-aligning hi-res textures: now takes the WorldPanning flag into account

- Fixed a problem in the linedef info panel where the linedef numbers was displayed instead of the sidedef number
- Fixed a problem where dragging geometry and things onto the window title bar locked up DB2
- Fixed a problem with wrong texture offsets of hi-res textures