Merge branch 'feature-functionObjects' into 'develop'

Feature function objects

Lots of updates migrated from internal development line

### Updated functionObjectFile
Old code maintained a list of file pointers, and provided a clunky interface to output to file.  Although OK for function objects that only created a single file, those that created multiple files were required to refer to each by an index and making it very easy to introduce errors.
The new code simplifies the functionObjectFile class so that it provides helper functions to create and write to files, and no longer maintains a list of file pointers.  Instead, each function object must create and take responsibility for all of the file streams that it requires.
Changes propagated across dependencies:
* fieldValues
* forces/forceCoeffs
* yPlus
* fieldMinMax
* residuals
* regionSizeDistribution
* fieldMinMax
* cloudInfo

### Created new functionObjectState
Previously, if function objects required to store data on disk to en...