Cleanup performance __str__ formatting

[jonnydyer]

Ugly now:

Status:
Equillibrium Computed: False
Properties Computed: False
Performance Computed: False
Composition:
METHANE - 1.000 mol
OXYGEN (LIQUID) - 1.000 mol
======= Chamber =======:
Pressure: 10.000 atm
Temperature: 2549.8 K
Enthalpy: -2047.491 kJ/kg
Int. Energy: -3376.014 kJ/kg
Gibbs Free Energy: -39958.401 kJ/kg
Entropy: 14.868 kJ/kg-K
Molar Mass: 15.958 g/mol
dV_P: -1.000
dV_T: 1.000
Cp: 2.675 kJ/kg-K
Cv: 2.154 kJ/kg-K
gamma: 1.242
Sound Speed: 1270.2 m/s

Ae/At: 0.00000
A/dotm: 0.00000 m/s/atm
C*: 0.00000 m/s
Cf: 0.00000
Ivac (m/s): 0.00000
Isp (m/s): 0.00000
Isp/g (s): 0.00000

======= Throat =======:
Pressure: 5.552 atm
Temperature: 2271.2 K
Enthalpy: -2785.802 kJ/kg
Int. Energy: -3969.178 kJ/kg
Gibbs Free Energy: -35858.463 kJ/kg
Entropy: 14.562 kJ/kg-K
Molar Mass: 15.958 g/mol
dV_P: -1.000
dV_T: 1.000
Cp: 2.623 kJ/kg-K
Cv: 2.102 kJ/kg-K
gamma: 1.248
Sound Speed: 1215.2 m/s

Ae/At: 1.00000
A/dotm: 175.39810 m/s/atm
C*: 1753.98100 m/s
Cf: 0.69281
Ivac (m/s): 2189.00591
Isp (m/s): 1215.17275
Isp/g (s): 123.91314

======= Exit =======:
Pressure: 0.010 atm
Temperature: 533.4 K
Enthalpy: -6870.379 kJ/kg
Int. Energy: -7148.318 kJ/kg
Gibbs Free Energy: -14801.680 kJ/kg
Entropy: 14.868 kJ/kg-K
Molar Mass: 15.958 g/mol
dV_P: -1.000
dV_T: 1.000
Cp: 1.999 kJ/kg-K
Cv: 1.478 kJ/kg-K
gamma: 1.353
Sound Speed: 587.5 m/s

Ae/At: 51.02182
A/dotm: 8949.12950 m/s/atm
C*: 1753.98100 m/s
Cf: 1.77069
Ivac (m/s): 3195.25638
Isp (m/s): 3105.76509
Isp/g (s): 316.69990