world files and locale

[warmerdam]

When operating in the C locale, GDAL cannot read world files using commas in place of a period as the decimal point (ie. typical of the "de" locale for instance).

Please modify the worldfile reading code to support either "." or "," as the decimal place regardless of the working locale. Basically, use the CPLAtof() function in place of atof().

(see GDALReadWorldFile() in gdal/gcore/gdal_misc.cpp)

Make sure a test of this is added to the test suite.

[warmerdam]

I'm working on this one tonight. 

[warmerdam]

I have added a CPLAtofM() in cpl_strtod.cpp which accepts either "," or "." 
regardless of locale.  It turns out that CPLAtof() only accepts "." regardless
of locale. 

Also added this into GDALReadWorldFile() in gdal_misc.cpp, and also the
.tab reader and the RPC metadata reading. 

Also added a test for this functionality in autotest/gdrivers/png.py via
the new test.wld mixed locale file in data.

All changes are in trunk.  I'm considering backporting to 1.4.x.

[warmerdam]

I have confirmed correct operation on windows, but attempts to merge have
been so far unsuccessful.  The changes are in:

 -r 10716:10712

Revisit tomorrow...

[warmerdam]

Patch backported to 1.4 branch.