Add config option to multiply EMC transmutation energy cost

[James103]

Fixes #20.

My testing indicates the new config option works as expected.
With transmutationPowerMultiplier set to 0.0, one can transmute as much as they want without spending any additional energy besides the passive drain from the module.
With transmutationPowerMultiplier set to 1.0, its as if nothing changed.
With transmutationPowerMultiplier set to something large like 9999999999999999999999, transmuting a single piece of cobblestone drains all energy stored in the ME network.
With, transmutationPowerMultiplier set to 0.0005, transmuting EMC and charging Klein Stars both cost the same amount of energy (this may be a good lower limit if 0 isn't). Anything lower and the energy cost to charge a Klein Star exceeds the energy cost to transmute the same amount of EMC on items.
With transmutationPowerMultiplier set to 0.000001 and Project Expansion installed, transmuting a Fading Matter (worth a trillion EMC) only costs around 2 million FE instead of 2 trillion FE. Lower values reduce this cost.

As this is part of the common config (like the other config options), a full restart of the client and server is required to apply any changes.

[62832]

Looks good. Many thanks for the contribution.