Added parameter directions to function parameter documentation.
Added new experimental FAST_STREAM_FUNCTIONS compile time option to speed up stream transfers at the expense of a higher FLASH consumption (needs testing to verify improved throughput).
Fixed incorrect ENDPOINT_EPNUM_MASK mask preventing endpoints above EP3 from being selected (thanks to Jonathan Oakley).
Removed STREAM_CALLBACK() macro - callbacks now use regular function definitions to clarify user code.
Removed DESCRIPTOR_COMPARATOR() macro - comparators should now use regular function definitions to clarify user code.