improved error handling of module loading
changed temporary path for testing IO to tmp://
Added check to make sure a type responding true to isAbstractDataType is not actually a void type instead
Merge branch 'master' of github.com:cwi-swat/rascal
added basic support for concrete syntax fragments to type checker
fixed error message for importer
Merge branch 'master' of github.com:cwi-swat/rascal
Merge branch 'master' into rascal-to-jigll