fix bug in delay_until and disable emulation
calibrate scale

Note that calibration using only integers (and long) does not work very
well. It seems as if we need floats. Measurement works for <20g quite
well (about -/+1g) but not at all for >100g. I assume this is simply
because I had to round the ADS1231_DIVISOR.
fix turn_until function

We cannot check the weight after each servo step, it slows down the
servo.
adjusting many config parameters

This are live tested values, but still not perfect.
add some debug msgs and some more debug code
add 2do list
calibrating weight using floats
fix wrong type and add debug msgs
add links in 2do list
change servo PIN
remove warning "remove weight from scale"
add item to 2do list
adjust config parameters
add offset to last_pour_pos
turn down fast to fixed position instead slowly

Instead of turning the bottle down slowly until a gain of weight is
measured, this branch turns the bottle fast to a fixed position.
Therefor last_pour_pos was removed.

Advantages:
 - The bottle pouring position is independent of the filling level.
 - The whole pouring procedure will be faster.

Disadvantages:
 - We cannot estimate the bottle filling level using the last_pour_pos.

This is not tested yet. Probably TURN_UP_DELAY needs to be increased
significantly.
add links for protothreads to 2do
adjusted for final bottles (square cross-section)
adjustment for leonardo and new scale
add posibility for more bottles
WIP random changes