BUG: resolve some decomposeParDict problems (issues #60, #265).

- Cleanup/centralize handling of -decomposeParDict by relocating
  common code into argList. Ensures that all processes receive
  identical information about the -decomposeParDict opton.

- Only use alternative decomposeParDict for simpleFoam/motorBike
  tutorial so that this will be included in the test loop for snappy.

- Added Mattijs' fix for surfaceRedistributePar.