Fixed a few examples.

examples/games/matching pairs.js :
js file now loads, and the UI can be seen and interacted with.
replaced game.time.now with game.time.totalElapsedSeconds()
examples/input/pixel perfect click detection.js
fixed two instances where the 'bunny' variable was referred to as 'b',
an undefined variable.
Merge pull request #20 from SherlockSolastice/master

Fixed a few examples.