New levels + fix for issue #46

Eight of them, to be exact. Some of them are quite hard to get all the treasures in, so that might keep the testers busy for a while :p

All of the platforms in these levels have one of the dimensions specified in #29. (Yes, the boxes in level 7 are four platforms stacked on top of each other.)

In addition to that, a few small changes were made:
* Issue #46 is fixed. (Bug46.xml demonstrates this bug if you play it on a branch without the fix.)
* The number of attempts that the player gets is now read from the level XML file (defaults to 3 if not specified, with a console warning message).
* Renamed the 'length' attribute on the platform to 'height'.

I was going to fix a bug with the ball bounces stat as well, but I suspected that I didn't do it correctly, so that's why there's a commit where I reverted my fix for that. It's so minor that I don't want to potentially break other things at this point.

Edit: Forgot to mention that you still have to change SetupTestLevel() if you want to test these. Michael is going to try to get the level select screen to read the levels and allow the user to choose which level to play.

Oh and here's a screenshot of level 5 :)

![level5](https://f.cloud.github.com/assets/1811645/404514/74079338-a94e-11e2-9628-dcf22ef2ef3c.PNG)