Fixed a bug in the interpreter that was only allowing lambads to have single character paramater names.
Extended TestSuite for a wide variety of tests of functions such as:
	1) Defining single parameter functions
	2) Definng multiple parameter functions
	3) Creating closures
	4) Passing functions as arguments to functions
	5) Inner function referencing its own and outer enclosing functions scope
	6) Inner functions referencing and modifying global scope variables
	7) The crowning jewel: recursive factorial function definition and execution