Fix up demo documentation device compatibility list to be as general as possible to reduce changes required as Atmel releases more devices within the same USB AVR series.

Remove information about 64 bit Windows OS signing requirements for the CDC based demos -- apparently the native CDC driver can be installed without first disabling the OS's driver signing requirements.

Documented FAST_STREAM_TRANSFERS compile time option.

Reduced the TCP window size for the RNDIS demos (Class and LowLevel) to make them compatible with the AT90USB64x.

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.

Corrections to Keyboard demo.

Removed AVRISP_Programmer project due to code quality concerns.