Only white space changes (indent 2, no TAB's)

We're using indent 2, which is more or less standard for Arduino. Also
I don't like the use of TAB, unless they represent 8 spaces.
Merge remote-tracking branch 'nickl/master'
Use stdint.h instead of inttypes.h because we only need the types

inttypes.h (despite the name) is used to give all the printf format stuff
and we don't need that.
Add .gitignore
Add first set of doxygen comments
Add LGPL
More comments converted to doxygen style
Replace the delay by a while loop waiting for the ADC to complete

Notice that this code is not "watchdog" safe. If the device never completes
the ADC it will hang forever.
Merge remote-tracking branch 'nickl/master' into for-nick
Replace hardcoded constant with a formula to compute the TWBR value
A few changes in comment