Adding .deepEqual() and .strictEqual()

[estilles]

In response to issue #21 I propose adding the following two aliases:

• Must.prototype.deepEqual as an alias of Must.prototype.eql
• Must.prototype.strictEqual as an alias of Must.prototype.equal

Unit tests and docs included

[moll]

Hey, thanks for the contribution!
Did you change your mind before I had a chance to react? :-)

[estilles]

Let me make some changes and I will resubmit.