* Units: Add unit for currency - South Korean Won

* Units: Add support for 'femto' and 'pico' decimal SI prefix

* Units: Expand library of energy units

Add:
Power - Giga-watt (useful for viewing metrics of power flow through large-scale electrical infrastructure)
Electrical Resistance - Kilo-ohm, Mega-ohm (useful for viewing metrics of energy storage e.g. internal resistance of a battery and more)
Electrical Capacitance - Farad, Micro-farad, Nano-farad, Pico-farad, Femto-farad
Electrical Inductance - Henry, Milli-henry, Micro-henry

* Units: Add unit test for currency ₩

* Units: Add unit tests for energy units