Fix bug with integer truncation in ASSERT_EQUALS
Fix expected value for testSetFrequencyParameter
Fix heap corruption in removeObserver
Ignore a bunch of Visual Studio generated files
Merge branch 'master' of https://github.com/teragonaudio/PluginParameters
Add documentation for building test suite
BooleanParameter sets internal value before calling super

If this is not done, then any listeners will receive the wrong value
in getValue(). BooleanParameter is a bit different than the others in
that it also has a copy of the value as a field in the subclass.

Also added test case proving bugfix.
Add VoidParameter type
Reorder test suite a bit
Fix some bugs in triggering observer callbacks

StringParameter was not notifying observers at all, and callbacks were
being made when setting the value to itself. Both issues have been
fixed with failing tests.