Add initial LOVE GUI setup
Move initialization calls into love.load()
Began implementing game functionality using a OO scene approach
Add playing card images
Massive changes further implementing GUI

The core game mechanics should now be available, but the game
pauses waiting for input from the human player.
Add card hover/selection indicators
Play cards using a selected flag
Continue implementation of GUI
Substantial refactor of code organization
Fix card image paths on case-sensitive filesystems
Update copyright year
Fix quit event for Love 0.8.0
Refactor the notion of advancing turns and players

Instead of using a turn_over flag in the player list and then
advancing the player accordingly, there is now an advanceTurn()
and advancePlayer() method. This better matches how the game works
as the turn can advance without the player.

This also fixes a bug where the turn was not advancing after the
initial card was played.
Allow hand cards to be selected with number keys
Fix human players not playing cards
Remove unused name field from CardPile objects
Refactor card selection and turn execution

A turn now consists of selecting cards followed by executing the
turn. The executeTurn() function takes care of playing the cards
or picking up the discard pile, as necessary.
Move middleclass to a library subdirectory
Fix quit event at game over screen
Clean up input callback guards