Ignore Xcode generated project
Add header files to build

Otherwise they won't be visible in Xcode generated projects
Rename PluginParameterObserver -> ParameterObserver
Rename PluginParameter -> Parameter
Rename PluginParameterSet -> ParameterSet
Rename ThreadsafePluginParameterSet -> ConcurrentParameterSet
Rename ENABLE_MULTITHREADED -> PLUGINPARAMETERS_MULTITHREADED
Indenting
Indenting
Method should take size_t, not unsigned int
Fix some compiler warnings in test suite
Split multithreaded tests to own file

This makes it very easy to test both sides of PluginParameters without
having to flip the PLUGINPARAMETERS_MULTITHREADED constant and rebuild.
Introduce BlobParameter class
Add tests for BlobParameter
Remove getDisplayText from Boolean/String parameter

What was this method supposed to do again?
Comment cleanups
No longer need hacky friends tester hook!
Introduce DataParameter class

This new abstract class is designed for parameters which hold
non-calculation data, such as blobs or strings. Test cases added.
Method should require size_t, not int
Indenting