More Bug fixes, balancing changes, polish

Hey there surgeons!

Had an update patch just.. geez, 20 hours ago? Well, I'm back with more! Thanks to Teh_Bucket for his insightful comment with some suggestions / bugs.

Here's the changes:

-Shrunk the radio text to accommodate bigger track / band names.

-Fixed a bug where you couldn't buy procedures you had exactly enough money for (Thanks Teh_bucket!)

-Added a few new music tracks

-Correctly curing a patient now awards $20 in addition to your payment per symptom.

-Added a new building difficulty mechanic. Every few days, more complicated patients begin to arrive to be cured. This should give new surgeons a lot more space to figure out cures and experiment with game mechanics.