Real Fuels Improvements

Here's the improvements for Real Fuels I'd like to contribute.
I've added a number of improvements to the ModularFuelTanks.cs code:

* Ability to specify fills using SI prefixes - ie:  40k for 40000
* Optional utilization tweaking - set a flag in MFSSETTINGS and every tank gets tweakable utilization.
* Ability to switch tank types in the editor
* Better compatibility with ProceduralParts

Here's how to do the utilization tweaking. Default utilization is 86%, but this can be changed if desired.
````
@MFSSETTINGS[MFSSettings]:AFTER[RealFuels]
{
	%partUtilizationTweakable = true
	//%partUtilizationDefault = 86
}
````

Here's how to offer multiple tank types:
````
PART
{
    //...
	MODULE
	{
		name = ModuleFuelTanks

		type = Default
		typeAvailable = Default
		typeAvailable = Balloon
		typeAvailable = BalloonCryo
		typeAvailable = Cryogenic
		typeAvailable = ServiceModule
    }
}
````

I've done a fair bit of testing and it seems to work quite well. Would love for this to make it into the next release of MFT / RF