calc: Add more unit types to the unit conversion

Created an attachment (id=6801)
Patch that adds the new units.

Adds more unit types to the unit converter. I also took the liberty of adding units for the ones that were previously commented out.

However, this only fully implements it for the English language(en-US.rc). I'm not fluent enough in the other languages to add the values as I do not know what some of the measurements are called in them.