Added Continue to the core.
Merge remote-tracking branch 'origin/scope-rewrite' into scope-rewrite

Conflicts:
	base/python-desugar.rkt
Added Continue to the rest of the stack.
Refactoring builtin classes and lib functions to mesh with new lexical phase.
More refactoring to make lib-functions work. Added VPointer for aliasing purposes.
More refactoring in lib-bindings. Fixes for assertRaises. 15 scope tests passing.