- Added Lexeme and LineNumber facade properties to TokenSAR for convenience.
 - Added SymbolicSAR abstract class that temporary, literal, and identifier SARs will derive from.
 -Added operator_sar class.
- Made OS a stack of operator_sar
- Added iPush that takes zero arguments and takes the token from the Lexer's current
- Added oPush with support for '=', '+', '-', '*',and '/' operators
-Added stubs for '+', '-', '*', '/' operators

-Added functions that test compatibility, and generate errors if type are incompatible.
Re-added SymbolTable.clear() to SyntaxTest so that Semantic Test can stand alone.