Automatically initialize PETSc in flcbdfWrappers

* Simplify Comm init so it takes no arguments
* Assume sys.argv is default argv to pass in to PETSc
* Remove PETSc database options
* Automatically initialize DAETK and Comm/PETSc in flcbdfWrappers
* Replace DAETK-Comm with a simple Python comm
* Add some basic tests to verify Comm
* Remove Comm.init() from a few places it is no longer explicitly needed
* Replace Py_PETSC_COMM_WORLD with PROTEUS_COMM_WORLD
With regards to the "two PETScs" issue, without thinking about it much it would be safe and a good idea to patch daetk to ensure that PETScInitialized has been called.  I don't have a deep understanding of how daetk interacts with Proteus, so I'd have to look harder for a better answer about what else you could do.