Remove extern "C" linkage from MPI user function definition in
an attempt to address build failure on amber12 vs9 MPI dashboard.

Don't use system headers before vtkSystemIncludes.h is included
to address build failure on  p90n03.pbm.ihost.com AIX xlC dashboard.

Temporarilly silence warning about implicit cast from double to int
while I work on the fix and validate it.

Order functions so that they're defined before used in an attempt
to fix "redeclared w/o dllimport after referenced" warnings on amber12
win32 mingw dashbaord.

Fix dllimport/export attributres on nested class in vtkParallelTimer

Fix int to bool warnings vtkPPainterCommunicator

Change-Id: I08a63dad92dcd3b86acfae9551508a04737a1122