Add instructions to compile avrdude from source with Xmega bootloader patches.
Add instructions to compile avrdude from source with Xmega bootloader patches.

chrism333/xpcc,dergraaf/xpcc,dergraaf/xpcc,chrism333/xpcc,dergraaf/xpcc,dergraaf/xpcc,chrism333/xpcc,chrism333/xpcc