Two important bug fixes for race conditions in S-Net reference counting.
Make fix for two race conditions dependent on presence of
HAVE_SYNC_ATOMIC_BUILTINS.  Add comments to explain the situation.
change outdated C4SNet api usage into current.
Modified to do division hashing with ideal primes. Remove compare
functions. Allow to iterate over the hash table.
Fix indentation.
Free input_stream when distributed. Moving commandline parsing to
dedicated function SNetInParseOptions.
Add SNetRuntimeGet. Add dummy functions for Distributed Front stuff.
Implement distributed computing for Front.
More tests for Distributed S-Net.
Also build Distributed Front. Make compile_cmd + link_cmd executable.
Changes to the common runtime for Distributed Front.
This includes some fixes to the MPI layer.
Merge Distributed Front from branch 'par'.