Fix contributed by Nath Gopalaswamy to large file problem reading
netCDF classic or 64-bit offset files that have a UINT32_MAX flag for
large last record size of a variable that has values larger than 1
byte.  This problem had previously been fixed for *writing* such data,
but was only tested with an ncbyte variable.  Fixed test to
demonstrate problem and the fix.

More updates to chunking documentation, cosmetic fixes for some
"--option=" documentation that doxygen turns into mdash.


git-svn-id: https://sub.unidata.ucar.edu/netcdf/trunk@3271 2e3060e4-1ed8-cf1f-9cc2-9586e844a556