forking  this problem to work on possible solutions.
fixed  the mem leaks in the partviewer, reset function seems to actually work correctly...  I missed another leak that I was not accounting for.
Merge branch 'frameMemLeak' into partio4Maya
this adds the  partio base code for  a "Reset" command  to  the partio lib
which hopefully will be able to  fix the mem leak in the maya plugins now  as well
fixed  partio4Maya  visualizer and  instancer  memory leak,  would still like to  implement this better in the  partio core.