add glcd backlight

added backlight function to demo sketch
Merge pull request #58 from herrfeuer/patch-1

add glcd backlight
fix baud rate for use as "Arduino as ISP" programmer
report more info about incoming IR data
start on new from-scratch RF69_compatibility driver
port more code, not working yet
reception works in polled mode
Merge branch 'rf69'
allow using the RFM69 module in RF12 compatibility mode

- polled mode
- receive only so far
- no low-power stuff, several rf12_* functions are dummies
fix rf69_config
fix send and header flags logic
oops, revert default settings
add interrupt code for RSSI reporting in RF12demo

- RF12demo now reports RSSI as last value, if supported
- example: OK 3 54 175 25 0 (-41)
- power up default now starts with quiet flag set (“1q”)
- default in GitHub now has DATAFLASH set to 0
- version number bumped to 11, i.e. “[RF12demo.11]”
fix RSSI calculation
cleanup
switch to an interrupt-driven implementation
tried to fix group 0 reception
oops, RF12demo bad default sneaked in again
report full resolution rssi when in hex mode ("1x")
better send flush logic, allows sleeping in sendWait