[core.fow.ui] extended XtextBuilderParticipant to run the ant buildfile
after invoking the generator, added an error marker for build problems,
and modified the ant buildfile generation in DotGenerator.xtend for
execution with AntRunner. Issue #3
Merge pull request #26 from protossoftware/ant_buildfile

[core.fow.ui, generator] merge branch for issue #3 (ant buildfile integration)