Implement the following functions in stack/TestingStack.java:


public static <T> boolean areEqual(Stack<T> s1, Stack<T> s2)
* Checks if the two stacks have the same items in the same order
* Compare two objects using .equals() method


public static <T> void reverseStack(Stack<T> s)
* reverses the stack


public static <T> Stack<T> cloneStack(Stack<T> orig)
* creates a copy of the orig
* when the function returns, orig must be in 
* the same state as it was originally 


public static <T> void swapStacks(Stack<T> s1, Stack<T> s2)
* swaps the content of s1 and s2

