Fixed some memory leaks
Vectors can now be +='d
readyText no longer takes unused x and y
Added WorldTips, which are tooltips for Entities
Defined in a level's .json via "msg": "My Message"
Moved RenderLayer from Entity's constructor to Drawable's
Added basic constructor for Drawable with just a RL
Removed custom drawing code for Hud's Hearts (now just in RL_HUD)
blockTDs map is now properly destroyed on shutdown