netcdf-c

- Fix NCF-158 to modify ncgen flag defaults.
- Fix NCF-157 to modify DAP code to support
  partial variable retrieval.
- Fix of NCF-154 to solve problem of ncgen
  improperly processing data lists for variables
  of size greater than 2**18 bytes.
- Fix ncgen processing of char variables that have
  multiple unlimited dimensions.
- Partly fix Jira issue: NCF-145 (vlen issues).
- Benchmark program nc_test4/tst_ar4_*) requires arguments
  and should only be invoked inside a shell
  script; fixed so that they terminate cleanly
  if invoked with no arguments.
- Fix the Doxygen processing so it will work
  with make distcheck.
- Begin switchover to using an alternative to ncio.
- Begin support for in-memory (diskless) files.