Add support for RUMBA thermocouple add on
 Add support for RUMBA thermocouple add on
fixed wrong pin initialization when using temperature 2 pin input
fixed wrong compare for min temp check of heater 1 and heater 2
Merge pull request #479 from MStohn/thermocouple

BUGFIXES for temperature.cpp / add RUMBA thermocouple support
Merge branch 'marlin_upstream' into jmil_upstream