start working on tao-in-petsc.
fix issues on enable_petsc_tao and updating demos and tests
remove FindTao cmake module
tiny fix
Remove some work-around code for PETSc 3.2, fixes Issue #287.
Require PETSc version >= 3.3.
Minor fix in new vector test.
Some fixes for 64-bit PETSc.
Merge branch 'cmaurini/tao-in-petsc'
Merge branch 'garth/fixes-for-petsc-64'
Merge branch 'master' into garth/fix-issue-287

Conflicts:
	CMakeLists.txt
Add MPI_LONG_LONG type in MPI wrappers.
Merge branch 'garth/fixes-for-petsc-64'