Small refactoring tile types names.
Add original imgId to tile.
Merge branch 'master' of https://github.com/gecube/opencaesar3 into vs2008-added

Conflicts:
	oc3_gui_tilemap.cpp : resolved
	oc3_roadpropagator.cpp : resolved
	oc3_tilemap.cpp : resolved
	oc3_tilemap.hpp : resolved
Fix meadow clearing such original game. Without changing terrain tile picture.
Merge pull request #40 from dalerank/master

get fixes