Petscinfo File:Func():Line

It's tricky figuring out exactly where every PetscInfo() call is coming from, but now each call prints at least a little more information. Since printing the full path of the file (or at least the full path given to the compilers) is useless clutter I also introduce PETSC_BASE_FILE_NAME which converts path/to/petsc/src/ksp/ksp/interface/iterativ.c to iterativ.c. This aliases either to __FILE_NAME__ (a gcc extension), a c++11 constexpr chain, or plain old __FILE__ if all else fails.