Migrate tests to CppUnit

Hi,

I have migrated existing tests to CppUnit framework. I hope this will ease development and maintenance of unit tests. I have converted exisitng tests for XML and H2Core::Pattern to new framework, as well written new tests for H2Core::ADSR class. While writing that test case, I discovered a bug in Decay and Release phases, and fixed it. I plotted graphs of ADSR envelopes befor and after the bugfix:
![before](https://cloud.githubusercontent.com/assets/1619113/2561321/1d037686-b80e-11e3-93e9-41c3dca56293.jpg)
![after](https://cloud.githubusercontent.com/assets/1619113/2561323/2552b63a-b80e-11e3-8025-c5abdad8ac18.jpg)

There's one regression: Rubberband tests have not been converted yet.