newRPL: Handling of units

[Claudio L.]

For those wishing to test this, I updated the ROM image in the usual place (not going to advertise it since it's a minor update)
The changes are:

* Added consistent named units for galUK, ptUK,qtUK, buUK and pkUK, as well as their Canadian counterparts. Didn't add tspUK and tbspUK.
* Added various speed shortcuts
* Added gmol and lbmol units (although gmol is just an alias, for naming consistency it needs to be there)
* Added acceleration menu with various shortcuts
* Added various shortcuts for power and electricity
* Added the turn _tr but not the gon, it's easy to define the alias if somebody doesn't like _grad.
* Added _spat, but not the square degrees and variants, as they would choke the parser.
* Redefined rpm as 1_tr/min
* Added shortcuts for viscosity
* Fixed inH2O definition
* Renamed Torricelli to _Torr and fixed its definition
* Redefined calorie as cal=4.184_J. Created calIT=4.1868_J
* Redefined Btu as 105505600_J (ISO variant). Created BtuIT with the IT definition.
* therms are now based off of ISO Btu, therefore are thermEC which was intended from the beginning
*Added dB as a non-dimensional unit

None of those tonne equivalent or liter equivalent units were added.

Unrelated to units, there were only 2 changes:
* Auto-OFF time set to 2 minutes by default
* Fixed glitch that left intermediate arguments in the undo stack.

As usual, test, report and comment. Thanks for the help polishing this module, and feel free to bring up more issues.