First cut at AST.
First cut at AST.

git-svn-id: https://svn.sable.mcgill.ca/mclab/Project@638 89b902b4-d83f-0410-b942-89f7a419ffdb

Migrated from Sable/mclab@aa937b9c1452f3bec6073b6cdbfce6c0aa6873fb

Sable/mclab-core,Sable/mclab-core,Sable/mclab-core,Sable/mclab-core,Sable/mclab-core,Sable/mclab-core,Sable/mclab-core,Sable/mclab-core