[Dart] dart and clean build

[Bill Hoffman]

Should the build stuff for msdev do a clean?  
It removes the .dsp files and other files that may
be hard to recover from a command line build.

The unix build does not sort of clean.  It is up to the
user to make sure things are clean before the build.


For CMake and VC I do this:

cd //c/hoffman/Dart
cvs update -dAP
cd //c/hoffman/CMake
cvs update -dAP
cd //c/hoffman
# here is the clean
rm -rf CMake-vc-dashboard
mkdir CMake-vc-dashboard
cd CMake-vc-dashboard
echo -e DART_ROOT:PATH=c:/Hoffman/Dart\\nMAKEPROGRAM:FILEPATH=msdev > CMakeCache.txt
/cygdrive/c/hoffman/CMake/Source/cmake ../CMake
msdev CMake.dsw /MAKE "Nightly - Win32 Debug" /BUILD


I don't think it is Build.tcl's job to clean.

-Bill