Beginning of new tile system
Added some warnings and asserts
Merge branch 'master' into tiles

Conflicts:
	client/include/sanguis/client/load/tiles/context.hpp
	client/src/client/load/tiles/context.cpp
	client/src/client/load/tiles/set.cpp
Fix projectile build
Output which tiles are missing
Added nothing_concrete_wall to tiles
Draw non connecting tiles as before
Use make_int_range and fixed formatting of an exception message
added new doors tile; renamed to stairs
removed accidental tiles dir from master