Add some missing documentation to some of the library demos.

Moved USBtoSerial demo the Projects directory, as it is simply an expanded CDC demo. Added const qualifier to Endpoint/Pipe stream write routines.

Move new Class Driver powered demos to a new ClassDriver subdirectory, re-add old low level demos to a LowLevel subdirectory.

Seperated out OTG, Device and Host mode demos into seperate folders for clarity. Adjusted makefiles so that the path to the LUFA library can be set in one place.

Combined Keyboad and Mouse normal and interrupt driven host demos into unified Keyboard and Mouse host demos.

Corrections to Keyboard demo.

Removed AVRISP_Programmer project due to code quality concerns.

Incomplete non-functional BluetoothHost demo removed until it has reached a stable state to prevent confusion.