MSVS Option to disable project in solution build configuration

[GoogleCodeExporter]

What steps will reproduce the problem?
1. The project is always be enabled in the solution build configuration for 
Visual Studio.
ie. when there is a project that basically runs gyp to refresh the Visual 
Studio solution/project tree, this project is expected to be built manually an 
not as part of the solution build.

What is the expected output? What do you see instead?
Provide an option to disable a project from the solution build configuration 
for Visual Studio.
Basically line #314 should not be written if a flag exists to not include a 
specific project in the solution build configuration.
https://code.google.com/p/gyp/source/browse/trunk/pylib/gyp/MSVSNew.py?r=1613#31
4

What version of the product are you using? On what operating system?
trunk, VS2010, VS2012

Please provide any additional information below.

Code relating to line #314 included below for reference.

    f.write('\tGlobalSection(ProjectConfigurationPlatforms) = postSolution\r\n')
    for g in config_guids:
      for v in self.variants:
        nv = config_guids_overrides[g].get(v, v)
        # Pick which project configuration to build for this solution
        # configuration.
        f.write('\t\t%s.%s.ActiveCfg = %s\r\n' % (
            g,              # Project GUID
            v,              # Solution build configuration
            nv,             # Project build config for that solution config
        ))

        # Enable project in this solution configuration.
        f.write('\t\t%s.%s.Build.0 = %s\r\n' % (
            g,              # Project GUID
            v,              # Solution build configuration
            nv,             # Project build config for that solution config
        ))
    f.write('\tEndGlobalSection\r\n')

Original issue reported on code.google.com by ioannis.e on 25 Jun 2013 at 8:43