group terrain tile levels: physical/attribure #111
implement the basic texture manager that keeps track of assigned texture units #125
generate unique tile name #125
use TextureManager for terrain textures #125
and the ui #125
texture manager for the postprocessing textures #125
Merge branch 'textureManager_125' into temperature_111

Conflicts:
	libelemate/terrain/basetile.cpp
	libelemate/terrain/terraingenerator.cpp
	libelemate/terrain/terrainshadows.cpp
	libelemate/terrain/terraintile.cpp
	libelemate/terrain/terraintile.h
	libelemate/terrain/watertile.cpp
pass temperatures to the terrain base shader #111
temperature change event testing #111