firmware: Add utils header file
firmware: Update copyright year to 2014 in new files
firmware: Delete commented-out code in isp.cpp
firmware: Expose ISP reset/release functions
firmware: Add 8x8 font data

Thanks to Daniel Hepper.
https://github.com/dhepper/font8x8
firmware: Add text rendering API
firmware: Remove magic number for core writes
Normalize joystick axes so that 0 is centered

Instead of ranging from 0 to UINT8_MAX, let it range from
-UINT8_MAX/2 to UINT8_MAX/2-1, with 0 being neutral.
firmware: Add boot menu
firmware: Add USB gamepad control to boot menu