Fixes #2482

And also add proj_context_errno_string()

Revise gie 'expect failure errno XXXX' strings

cs2cs: add --area and --bbox  options to restrict candidate coordinate operations (fixes #2423)

Add option to allow export of Geographic/Projected 3D CRS in WKT1_GDAL

Currently the output of the cct utility is different between radians
and degrees (as expected by cct), because of a bug in cct:

$ printf "1 2\n" | cct -z 0 -t 0 +proj=pipeline +step +proj=unitconvert +xy_in=deg +xy_out=rad
  1.0000000000    2.0000000000        0.0000        0.0000

$ printf "1 2\n" | cct -z 0 -t 0 +proj=pipeline +step +proj=unitconvert +xy_in=deg +xy_out=deg
       1.0000         2.0000        0.0000        0.0000

The arguments to the printf format string are as follows:

 * radians: width 14, precision 10
 * degrees: width 13, precision  4 (this is by mistake. bug!)

After the suggested fix has been applied, output will be the same for
both radians and degrees:

$ printf "1 2\n" | cct -z 0 -t 0 +proj=pipeline +step +proj=unitconvert +xy_in=deg +xy_out=rad
  1.0000000000    2.0000000000        0.0000        0.0000

$ printf "1 2\n" | cct -z 0 -t 0 +proj=pipeline +step +proj=unitconvert +xy_in=deg +xy_out=deg
  1.0000000000    2.0000000000        0.0000        0.0000

The cause of the bug is that cct does test if it "has radians to output",
but "neglects" to test if it "has degrees to output", resulting in using
different arguments to the printf format string in the latter case.

The fix makes cct test if it "has either radians or degrees to output".

Remove proj_api.h