Pythia 8.200pre2 (71x)

Backport of interface changes for pythia 8.2.
Needs to be merged together with 
https://github.com/cms-sw/cmsdist/pull/1065/
Hi Lukas,
In 71x it seemed as though the code setting the flags was not present at all.  Was fastsim + pythia 8 really working already in 71x or only in 72x?