Glad it's working! Now there's still a minor issue that's easy to fix but completely optional. When you compile you'll see a warning:
Warning: Board HPs:avr:rhp doesn't define a 'build.board' preference. Auto-set to: AVR_RHP
Warning: Board HPs:avr:fhp doesn't define a 'build.board' preference. Auto-set to: AVR_FHP
Warning: Board HPs:avr:thp doesn't define a 'build.board' preference. Auto-set to: AVR_THP
That can be safely ignored but it gets kind of annoying if you're trying to watch for other errors/warnings. You can fix it by updating boards.txt to:
# See: http://code.google.com/p/arduino/wiki/Platforms
##############################################################
fhp.name=HoloProjector I2C FHP (Blue)
fhp.upload.tool=arduino:avrdude
fhp.upload.protocol=arduino
fhp.upload.maximum_size=32256
fhp.upload.maximum_data_size=2048
fhp.upload.speed=115200
fhp.bootloader.tool=arduino:avrdude
fhp.bootloader.low_fuses=0xFF
fhp.bootloader.high_fuses=0xDE
fhp.bootloader.extended_fuses=0x05
fhp.bootloader.file=holoprojector/hp_i2c_fhp.hex
fhp.bootloader.unlock_bits=0x3F
fhp.bootloader.lock_bits=0x0F
fhp.build.mcu=atmega328p
fhp.build.f_cpu=16000000L
fhp.build.core=arduino:arduino
fhp.build.variant=arduino:standard
fhp.build.board=AVR_FHP
##############################################################
thp.name=HoloProjector I2C THP (Red)
thp.upload.tool=arduino:avrdude
thp.upload.protocol=arduino
thp.upload.maximum_size=32256
fhp.upload.maximum_data_size=2048
thp.upload.speed=115200
thp.bootloader.tool=arduino:avrdude
thp.bootloader.low_fuses=0xFF
thp.bootloader.high_fuses=0xDE
thp.bootloader.extended_fuses=0x05
thp.bootloader.file=holoprojector/hp_i2c_thp.hex
thp.bootloader.unlock_bits=0x3F
thp.bootloader.lock_bits=0x0F
thp.build.mcu=atmega328p
thp.build.f_cpu=16000000L
thp.build.core=arduino:arduino
thp.build.variant=arduino:standard
thp.build.board=AVR_THP
##############################################################
rhp.name=HoloProjector I2C RHP (Green)
rhp.upload.tool=arduino:avrdude
rhp.upload.protocol=arduino
rhp.upload.maximum_size=32256
rhp.upload.maximum_data_size=2048
rhp.upload.speed=115200
rhp.bootloader.tool=arduino:avrdude
rhp.bootloader.low_fuses=0xFF
rhp.bootloader.high_fuses=0xDE
rhp.bootloader.extended_fuses=0x05
rhp.bootloader.file=holoprojector/hp_i2c_rhp.hex
rhp.bootloader.unlock_bits=0x3F
rhp.bootloader.lock_bits=0x0F
rhp.build.mcu=atmega328p
rhp.build.f_cpu=16000000L
rhp.build.core=arduino:arduino
rhp.build.variant=arduino:standard
rhp.build.board=AVR_RHP
##############################################################
That just sets the same build.board values that the Arduino IDE already sets automatically so it doesn't change anything except to fix the warning.