SH-4365 SH-4367 Conversion of mesh uploaders to llcorehttp.

With this checkin, legacy LLCurl is out of the mesh code.
Uploaders and responders are converted and functioning.  Logging
has been cleaned up throughout the code to use the macro form
with tag/subtag capability.  DEBUGS-level logging added for some
upload path milestones.  Better error information flow from
failed responses to viewer alert boxes but I'd really, really
like to do better here.  Mesh upload problems are completely
opaque as a user.  Minor cleanups (removed dead members,
method signatures tidied, less data conversion).  Could almost
call this complete, will likely have platform cleanups, however.