Added loop metaprogramming construct for multiple annotation member generation. See the example for simple usage.
Merge branch 'master' of github.com:DaMSL/K3-Core
Add purity annotations to all expression nodes.
Propagate purity annotations to declarations.
Merge branch 'master' of github.com:DaMSL/K3-Core into forkEngines
Remove unnecssary functions from collections
Improve StlDS and Map