Feature function objects

Lots of code migrated from internal development line, code tidying and a few fixes

Updated objects

• corrected Peclet number for compressible cases
• propagated log flag and resultName across objects

New function objects

• new fluxSummary:
  • calculates positive, negative, absolute and net flux across face zones
• new runTimeControl
  • abort the calculation when a user-defined metric is achieved. Available options include:
    • average value remains unchanged wrt a given threshold
    • equation initial residual exceeds a threshold - useful to abort diverging cases
    • equation max iterations exceeds a threshold - useful to abort diverging cases
    • min/max of a function object value
    • min time step exceeds a threshold - useful to abort diverging cases
• new valueAverage:
  • average singular values from other function objects, e.g. Cd, Cl and Cm from the forceCoeffs function object