added support for plus variables to the list pattern matcher. The problem was that the matcher works under the invariant that a failed list slice does not suddenly start succeeding by increasing the slice size. Plus variable do need this semantics, so some more specialization was needed in the list matcher to start with a non-empty slice in case of a plus list and the invariant still holds
Merge branch 'master' of github.com:cwi-swat/rascal
added experimental feature to parser generator, if you use a layout non-terminal in a syntax rule it will use that non-terminal instead of an automatic rule
Merge branch 'master' of github.com:cwi-swat/rascal