Make SPI and USART peripheral dispatch driver headers in preparation for a set of AVR32 peripheral drivers.

Add more include protection macros to give the user warnings when they try to manually include private driver header files, instead of the public driver headers.

More documentation changes for better module-level documentation rather than file-level documentation.

Fixed GenericHIDHost demo report write routine incorrect for control type requests (thanks to Andrei Krainev).

Removed Endpoint_ClearCurrentBank() and Pipe_ClearCurrentBank() in favour of new Endpoint_ClearIN(), Endpoint_ClearOUT(), Endpoint_ClearControlIN(), Endpoint_ClearControlOUT(), Pipe_ClearIN(), Pipe_ClearOUT(), Pipe_ClearControlIN() and Pipe_ClearControlOUT() macros (done to allow for the detection of packets of zero length).

Renamed *_ReadWriteAllowed() macros to *_IsReadWriteAllowed() to remain consistent with the rest of the LUFA API.

Endpoint_IsSetupReceived() macro has been renamed to Endpoint_IsSETUPReceived(), Endpoint_ClearSetupReceived() macro has been renamed to Endpoint_ClearControlSETUP(), the Pipe_IsSetupSent() macro has been renamed to Pipe_IsSETUPSent() and the Pipe_ClearSetupSent() macro is no longer applicable and should be removed - changes made to compliment the new endpoint and pipe bank management API.

Updated all demos, bootloaders and projects to use the new endpoint and pipe management APIs (thanks to Roman Thiel).

Updated library doxygen documentation, added groups, changed documentation macro functions to real functions for clarity.

Removed old endpoint and pipe aliased read/write/discard routines which did not have an explicit endian specifier for clarity.

Removed the ButtLoadTag.h header file, as no one used for its intended purpose anyway.