gmod_src: Added custom HTML control for the Lua editor

Revision 875
Added custom HTML control for the Lua editor Changed Files:
[ul]
[li]trunk/src_garrysmod/garrysmod/Library/cl_gl_vgui.cpp [/li][li]trunk/src_garrysmod/garrysmod/gmod_util.cpp [/li][li]trunk/src_garrysmod/garrysmod/gmod_util.h[/li][/ul]

Committed By Garry Newman