Added messages for FileNotFoundError and other exceptions.
Added messages for FileNotFoundError and other exceptions.

WhitmanH/learntris,tangentstorm/learntris,Shamash2014/spice_and_html,Shamash2014/spice_and_html,Larsharaldjoh/Tetris,BigRoss/learntris,LearnProgramming/learntris,Shamash2014/spice_and_html,BigRoss/learntris,lochanaeg/learntris,TylerLau/learntris,nbgraham/learntris,DTSCode/learntris-haskell,mosegontar/learntris,TylerLau/learntris