Update makgdal_gen.bat to generate project for autotest/cpp

[Mateusz Łoskot]

This patch updates makgdal_gen.bat to:

1. Generate separate .vcxproj file for GDAL C++ tests
   • The new project is created only if autotest/cpp folder exists (ie. source code tree downloaded from SVN/Git repo)
2. Add CPL_DEBUG and GDAL_DATA variables to LocalDebuggerEnvironment in .user file.
3. Use setlocal to keep the command prompt environment clean.
4. Update list of subfolders excluded from the main project.
5. Clean up / clarify usage instructions.

I'll appreciate review of my changes.

Next, I'd like to propose renaming of the script from makegdal_gen.bat to generate_vcxproj.bat, so the name reflects the purpose.

If we agree to rename it, I will update the Wiki pages where the old name occurs.

[Mateusz Łoskot]

Ups, I'm not being allowed to submit any files. Reported to admins: ​https://trac.osgeo.org/osgeo/ticket/1877

[Mateusz Łoskot]

Due to problems with attaching the patch I decided to submit the changes via GitHub PR: ​https://github.com/OSGeo/gdal/pull/195

[ilucena]

I haven't tried but I trust it will work fine since Mateusz is the primary user of that. The name change is also a good idea.

[Mateusz Łoskot]

@ilucena Yes, I use it myself and it works. I will merge into trunk. Thanks.

I will also rename.

I also have an idea to update the script so it generates a basic .sln file with the two .vcxproj attached. I may add it later, separate commit.

[Mateusz Łoskot]

Patch committed to trunk in r37389

[Mateusz Łoskot]

Renamed makegdal_gen.bat to generate_vcxproj.bat in SVN trunk r37390

[Mateusz Łoskot]

Wiki pages updated.

The current page is wiki:GeneratingVisualStudioProject