Added custom 2mhz/19200 bootloader

Added patch to optiboot source to compile a custom bootloader that runs
at 2mhz.  The fuses are now setup to divide the 16mhz external clock by
8 and brown out detect at 1.8V.  This should run at a more battery
friendly 2mhz down to 1.8V.
Fixed missing Power Net, spelling

Fixed Spelling of Arduino on silk and documentation.  Fixed missing
power net to ATMEGA328P processor