corrected ranges
make all internal functions static, rename

This prepares for fitting the revised Pack.c of packman into the
parallel GHC runtime system. The module should not export any
functions without need, and prefix all exported ones with "pm".

Exported:

int pmtryPackToBuffer(StgClosure* closure, StgArrWords* mutArr);
StgClosure* pmUnpackGraphWrapper(StgArrWords* packBufferArray, Capability* cap);