Added gmem support for libfabric.  Added proper endpoint exchanges for node info (IP address) and GMEM.  Passes fuirst 10 tests in the intrepid test suite.

ISSUES:

- libfabric is outdated (July timeframe)
- closing endpoint reports an error - needs to track it better
- runtime barrier (PMI) is used
- runtime exchanges (PMI) are excessive as we have a PMI barrier
  for each data exchange (three for now: GMEM, NID, shared memory
  name).  Need to rearrange init code to have only one PMI
  barrier (will require splitting init code into two routines -
  (1) contribute info to PMI, (2) get info on other threads