added support for multiple game layers
changed name of game layer type member
Merge branch 'dd_cb_gamelayers' into dd_cb_triggertiles

 is necessary,
Merge branch 'dd_cb_triggertiles' into dd_fb_teleporters

Conflicts:
	src/game/collision.cpp
	src/game/collision.h
fixed brush grabbing
forgot tile image
Merge branch 'dd_cb_gamelayers' into dd_cb_triggertiles
Merge branch 'dd_cb_triggertiles' into dd_fb_teleporters

Conflicts:
	src/game/editor/editor.h
	src/game/editor/layer_tiles.cpp
fixed weird last commit
Merge branch 'dd_cb_gamelayers' into dd_fb_teleporters

Conflicts:
	src/game/editor/layer_tiles.cpp
added missing flag toggler