Clean up RedlichKwongMFTP

[decaluwe]

Abstract

With the (in-progress) addition of the PengRobinson class (Cantera/cantera#641), which largely parallels the RedlichKwongMFTP implementation, it is apparent that there are a number of updates and changes that would make the latter class more robust, easier to read, and overall more consistent with the rest of the Cantera codebase.

Description

• Convert instances of doublereal to double
• Update and/or fix some variable names for greater clarify and/or brevity
• Add a test to the suite to evaluate the class calculations directly against the EoS (similar to PengRobison_Test::getPressure.
• This is just a partial list. A thorough evaluation and scrubbing of the class is merited.

[bryanwweber]

@decaluwe What's the status of this with respect to Cantera/cantera#641? Is there more to do related to this issue? Can it be closed?

[decaluwe]

I am guessing it is incomplete. @gkogekar may have addressed some of these in creating some functionality at the MixtureFugacityTP level, but other than that I'm not sure much has been done, here. I certainly would not close it, at this point. I'll try and take a look in the coming weeks.