Added LiFePO4 batteries & set as default

Added LiFePO4 batteries and set them as default. Voltages taken from this site: http://www.powerstream.com/LLLF.htm
Lower boundary set a little higher (2.2V rather than 2.0V) in order to have a safety gap.

Also deactivated console logging of the rov.lift function in tankcontrol.
corrected it