expose scope object and allow reassignment of scope object

Author: chrisdickinson

lib/index.js

@@ -146,6 +146,13 @@ function parser() {
   program = node
 
   stream.program = program
+  stream.scope = function(scope) {
+    if(arguments.length === 1) {
+      state.scope = scope
+    }
+    return state.scope
+  }
+
   state.unshift(node)
   return stream