removing an object with index larger than size doesn't seem to be working
junit test confirms that linkedList crashes when remove an object with too high an index
fixed the problem. was creating an object with value at index before checking if the index was valid thus leading to a null pointer exception
fixed LinkedList so it works when first element is removed or last element is removed. was getting null pointer exception because index + 1 was null when removing last element
still wasn't working, now LinkedList fully working