Changes tileset.cpp and tileset.h to try and address the problem of dfferent sized tilesets. However, it currently encounters a segmentation fault at line 231 of tilesetmanager.cpp
Fixes segmentation fault caused by destroying variables at the end of line 220 of tilesetmanager.cpp which resulted in pointers pointing to garbage.
Fully implements optimisations to reloading multiples of the same images - #825