ENH: ensightWrite function object - write .case file every time ensight data is written

Currently, the ensightWrite function object appears to only finish writing the .case file at the end of the simulation. It would be useful if this file was written out fully every time ensight data is written during the simulation. This would allow a user to check simulation results multiple times while the simulation is running by simply loading the .case file into EnSight or Paraview.