fix(urword): increase number of characters for integers and floats

[langevin-usgs]

There was a 30 character limit hardwired into urword. This seemed arbitrary and could cause problems for programs like PEST as described in #1638. This PR relieves this restriction and instead defers to the Fortran casting from a string to an integer to determine if there is a problem.

Simple fix is to change from

100 if (ncode == 2 .or. ncode == 3) then
      rw = ' '
      l = 30 - istop + istart
      if (l < 1) go to 200
      rw(l:30) = line(istart:istop)
      if (ncode == 2) read (rw, '(i30)', err=200) n
      if (ncode == 3) read (rw, '(f30.0)', err=200) r
    end if
    return

to

100 if (ncode == 2 .or. ncode == 3) then
      l = istop - istart + 1
      if (l < 1) go to 200
      if (istart > linlen) then
        ! support legacy urword behavior to return a zero value when
        ! no more data is on the line
        if (ncode == 2) n = 0
        if (ncode == 3) r = DZERO
      else
        if (ncode == 2) read (line(istart:istop), *, err=200) n
        if (ncode == 3) read (line(istart:istop), *, err=200) r
      end if
    end if
    return

Checklist of items for pull request

• Replaced section above with description of pull request
• Close 6.4.3 change in number of ASCII characters supported for casting to double #1638
• Added new test or modified an existing test
• Updated develop.tex with a plain-language description of the bug fix, change, feature; required for changes that may affect users
• Removed checklist items not relevant to this pull request

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