Fixed RSS-breaking issue in pressureCurve parser

Fixed RSS-breaking issue in pressureCurve parser (pressureCurve data with no tangents would throw an error)
Improved sanity checking in pressureCurve parser.
Moved pressureCurve parser code into a generic animationCurve parser: loadAnimationCurve() for any other curve data we need to handle.
revised pressureCurve (Kerbin, Duna) added Eve & Laythe

Revised pressureCurve data for Kerbin and Duna to produce smoother curves
Fixed tangents to avoid temperature failure issues (stock problem)

Added pressureCurve data for Laythe and Eve. (good luck taking off from Eve...)
Further revision to Laythe atmosphere

Extended Laythe atmosphere from 390 to ~900. (aerobraking should be possible at ~600 km)
(plus it's atmospheric envelope is freakin' huge)
Update RealSolarSystem.cfg
Merge pull request #3 from Starwaster/master

Fixed RSS-breaking issue in pressureCurve parser