Major refactor: switching to IL.Emit exclusively.  Removed type handlers, using BaseType descendants.  Complete through tuple comparison and basic identifier expressions.
IL.Emit: Compiling calls, var references, local functions, set, list.  Added Boolean, and Void types; completed Function type.  Numerous refactorings.
String comparisons; comperable sets and lists; improved nary selector emission; refactoring of operator emission for types; fixed empty set parsing.  Added test cases.
Scalar and nary restriction working by value and index.  Optional type.
Variable declaration and initialization.  Typedefs.  Working function selectors.  Nary derefencing.  Tuple derefencing.  Body of function to just expression.
Missed sdf in the SQL test project.
Major refactoring - split emission and compilation.  More data type support.
Completed IL rewrite.  Added separators and refactored function invocation.  Removed restrict, replaced with call.  Fixed issues with nested FLWOR.  Introduced "self" for call self-referencing.