Made AST conversion better.
Got more functions working with AST
Merge remote-tracking branch 'upstream/master' into ast-fixes

- This is a straightforward merge of @bptripp's stuff
- I'm going to go back and make another commit to better
  integrate our work
Got all ast conversion tests passing

- @bptripp's lambda function code is now fully integrated
  with my additions
Merge pull request #42 from hunse/ast-fixes

Ast conversion improvements from @hunse and @bptripp