Mixxx test suite

Based on Google Test

1. Build Mixxx using scons test=1. You'll get a mixxx-test binary alongside the usual mixxx binary.
2. Run mixxx-test. It will run every test in each of our test suites, and return to you the passes/failures, along with the tests that failed.

When we run this test suite, we will have higher assurance that our development efforts are eliminating bugs and at the same time, not regressing on old ones.

To add a test, all you have to do is add a source file to src/test/ which inherits from testing::Test. As an example, check out some basic ControlObject tests I added in src/test/controlobjecttest.cpp

To read more about how to use Google Test, check out this primer: http://code.google.com/p/googletest/wiki/GoogleTestPrimer

• Supported on our three main platforms.
• Since Google use it extensively, we know it's been tested in serious environments, and will continue to be a healthy project.
• Impressive support for a number of different kinds of tests (death tests, etc)