Tidy up String, Int32, Int64 and Boolean
Add Format method to String
Mark void as public
Add support for compiler to compile more deceleration & assignment statements

The following are all valid. var x = <rhs>, val x = <rhs>, x := <rhs>
Rename FType.Package to FType.DeclaringPackage
Fix up VGetLocal

Compiler generates code to get contents of variables.
VGetLocal properly formats self in toString
VGET LOCAL now highlighted in FILI output
Testbed stores last written code