wip for buzzer
Merge branch 'feature/dynaconfig' of https://github.com/BrewPi/brewpi-avr into feature/dynaconfig
Merge branch 'feature/dynaconfig' of https://github.com/BrewPi/brewpi-avr into feature/dynaconfig
fix for menu so that beer temp is displayed
Merge branch 'feature/dynaconfig' of https://github.com/BrewPi/brewpi-avr into feature/dynaconfig
Merge branch 'feature/megasupport' into feature/dynaconfig

Buzzer support for meag2560
Merge branch 'feature/dynaconfig' of https://github.com/BrewPi/brewpi-avr into feature/dynaconfig
Merge branch 'feature/dynaconfig' of https://github.com/BrewPi/brewpi-avr into feature/dynaconfig
Merge branch 'feature/dynaconfig' of https://github.com/BrewPi/brewpi-avr into feature/dynaconfig
printTemperature is always called with INT_MIN for invalid temperature - getBeerTemp()/getFridgeTemp()/getBeerSet()/getFridgeSet() and tempSensor->read() all return INT_MIN on disconnected, so the repepated checks for disconnected can be factored out.
Refactored common strings in lcd printState.

before
    Program Memory Usage  : 28732 bytes   87,7 % Full
    Data Memory Usage   : 698 bytes   27,3 % Full
after
    Program Memory Usage  : 28682 bytes   87,5 % Full
    Data Memory Usage   : 738 bytes   28,8 % Full
refactored compare and substract into updateWaitTime. Saves 48 bytes.
before (revA, leonardo)
    Program Memory Usage  : 28682 bytes   87,5 % Full
    Data Memory Usage   : 738 bytes   28,8 % Full
after
    Program Memory Usage  : 28634 bytes   87,4 % Full
    Data Memory Usage   : 738 bytes   28,8 % Full