Scalatest version bump
Better prettyprint for Bag
New Mapper and Fold API for FlatSyntax
Started porting semantics to FlatSyntax

- Fixes for nondeterm_1_subst (flattening of parallel composition)
Ported nondeterm_2_env to new syntax
Ported nondeterm_3_routed to new syntax
Fixes in nondeterm_3_routed
Ported nondeterm_4_grouped to new syntax
Added forgotten files
Small cleanup
Ported nondeterm_5_parallel to new syntax
Ported concurrent_6_thread to new syntax