In VS9 and previous versions, :VCReportError is the goto label
to jump to after a failed custom command. It stops the build
before it tries to go any further.
In VS10, :VCEnd is the correct label to use.
Create a method in the VS generators to provide the correct
line of script to use for each version of Visual Studio.
For more internal details, search for VCEnd in the
C:\Program Files\MSBuild directory.
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.