Make sure plotdata object always gets created.
Merge pull request #354 from ketch/better_controller_plotting

Make sure plotdata object always gets created.
Minor refactoring of I/O code (no change in functionality).
Fix I/O bug introduced in last commit.
Put options argument back in io/petsc.py read and write functions.
Status dictionary now refers to the whole simulation.

Also set +/- infinity values initially for cflmax, dtmax/min.
Merge pull request #358 from ketch/clean_up_io

Clean up I/O
Merge pull request #359 from ketch/fix_status

Status dictionary now refers to the whole simulation.