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.

Re-add signature byte defines to the DFU and CDC class bootloaders -- the SIGNATURE_x defines in the AVR device header files only exist in a newer version of avr-libc than is in the Debian repositories, causing build issues on Linux.

Added preprocessor checks and documentation to the bootloaders giving information about missing SIGNATURE_x defines due to outdated avr-libc versions.

Corrections to Keyboard demo.

Removed AVRISP_Programmer project due to code quality concerns.