added 'on_top_of()' function
apperently I changed something here but that was last night and I forgot
removed SDL_Rect to abstractObject and added get_x/y()
moved SDL_Rect to abstractObject and flipped set_size(x,y) to match set_pos
using new functions
Merge branch 'master' of https://github.com/russloewe/HammerCrest
merging the readme file