Removing execution permission from source files
Minor additional debug output for 1st pass of the checker
Modified TypeChecker and EffectChecker to ignore checking functions
that are not in the SymbolTable (e.g., template functions).
The specialized template code is still visited, however.
Added temporary fix to AST Traverser bug that causes revisiting the same
AST node multiple times. This fix prevents the checker from quiting
upon trying to re-insert a type for the same AST node into its symboltable.