netcdf-c

Github issue 134:

Their is an ambiguity in the DAP2 spec.  Section A.2 of the
dap2 spec says:
  "...The backslash character (.\.) MAY be used as
   a single-character quoting mechanism only within
   quoted-string and comment constructs.
      quoted-pair = "\" CHAR
   ..."
The underlying problem was to allow for " chars inside
strings by using \". However, this definition is overbroad.
It is not stated:
1. if the backslash is to be left in the string or not.
2. There is also an unstated, but related issue of what
   to do about e.g. '\n';convert to newline or not.

This change is to conform to libdap and it does the following:
1. The backslash is left in the string
2. Things like \n are left as is and it is assumed that
   higher level code will decide what to do with e.g. \n.