Created the 2nd part of assignment 2

This hasn't been tested yet but should be close to correct. I will attempt to
test and verify this in the next couple of days.
Added default SICStus install location to the README

Got tired of forgetting how to run the interpreter and added the line for easy
reference. I could always make a symlink, but meh, lazy! haha I'll probably do
that in a bit.
The equal functor is completely working and tested.

Assignment 2.1 is complete now.
 The element functor is completely working and tested.

Assignment 2.4 is complete now.
 The drop functor is completely working and tested.

Assignment 2.2 is complete now.
 The range functor is completely working and tested.

Assignment 2.3 is complete now.
Fixed the date of the code.
Added prettier comments.
Fixed commenting spacing.
Completed Assignment 2

Woohoo!