Removed scheduler and memory allocation libraries.
Added new EVENT_USB_StartOfFrame event in the library to indicate the start of each USB frame (when generated).
Removed Tx interrupt from the USBtoSerial demo; now sends characters via polling to ensure more time for the Rx interrupt.
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.
Further documentation improvements - removed file view from the main library documentation, replaced file references in the documentation with group references.