Add further clarification regarding new "test" APIs
Paul Hargrove has pointed out that some big SMP systems (e.g., from SGI) configure Torque differently - instead of listing each node name once/slot in the nodefile, they list the node only once and set an envar to indicate the number of procs/node being allocated. Add an MCA param users can set to indicate we are in such an environment, and then use the envar to set the slots. Error out if the mode flag is given, but (a) we don't find the PBS_PPN envar, or (b) we find a node actually listed more than once in the PBS_Nodefile.

cmr=v1.7.5:reviewer=jsquyres:subject=Support SMP mode in Torque