#10043 ssync: data sync does not work any more
Merge branch 'master' into test_merge
Add some advice to doxygen docs.
Implement HTTP Basic Authorization for sproxyd

and make the function that creates the Authorization header shared
between the CDMI and sproxyd backends.
Unit test dpl_set_log_func()
Remove extraneous \n from DPL_LOG() calls
Capture SSL errors in the log function too

instead of dumping them to stderr.
Add a trivial fake sproxyd server for testing

- extremely simple HTTP server
- can be started and stopped from test code
- server internal state is exported to a mmap'd file
- test code can examine server internal state (useful
  for verifying that Droplet is generating correct HTTP)