Adding == and < operators for descriptor classes
Marking get_descriptor_index() as const
Do not attempt to store descriptor if response != SUCCESS
Tidy up descriptor object deletion on destruction
Fixing multiple copies of the same descriptor in list.

Now we check if the descriptor is already present in the list
and update the existing entry.
Merge pull request #7 from audioscience/master

Pulling in upstream
Adding stream port input/output to OSX makefile
Marking get_descriptor_index() const in new descriptors
Merge pull request #31 from ajwlucas/master

Fix for multiple copies of the same descriptor in list