added matrix header file
fixed incorrect naming in matrix header and added petsc solver module
changed over loss operator to new notation and fixed up matrix header
fixed some redundant statements and simplified
change prod operator construction
added a vector class
changed over power iteration and added more methods
Merge branch 'master' into cmfd_clean
removed cmfd message passing and re-made dependencies
got rid of 2 group fixed data
changed comments and updated some parts of code
cleaned up comments and some bits of code
cleaned up cmfd input comments and bits of code
no longer need cmfd message passing routines
cleaned up comments in cmfd output
removed some useless cmfd vars and removed use mpi from global
added cmfd timers and output them at end of run
changed CMFD timer output to match convention
fixed comments in these modules
added compiler flags so that code compiles without petsc