V1.0 2007.10. Initial release 

v1.1 2007.10. Some error fixing, cleaning the code

v1.2 2007.11.
- corrected temperature coefficients of thermocouple
- outputs to LCD from string-tables

v2.0 2007.11
Hardware:
- heating and contrast voltage pump outputs exchanged: RC5/P1A=heating, RC4=contrast
- PSON moved to RA5
- a two-colour LED installed on +5VSB and PSON: orange in sleep, green in normal mode
- a red LED built in to indicate heating
Software:
- output bits modified refecting hardware changes
- heating output is now driven by PWM; PWM frequency is 245Hz
- timer0 acts as baudrate-interrupt generator and runs at ~9600Hz
