Re-add in flip, flip-ee, dfu and dfu-ee targets to project makefiles (thanks to Opendous Inc.)
Fix allowable F_CPU values comment in project makefiles.
Split out common defines/types from class drivers into a seperate common class driver directory.
Make central USB Class driver dispatch headers, used for both device and host modes.
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.