Introduce assertions for each type as in Vows
Added assertions for NaN

Use
x.should.be.NaN;
or
x.should.not.be.NaN;
isNaN now rejects all non-numbers
Closes #53 - 'a' and 'an' is now similar, 'have.type' replaces 'be.a'.
Added docs and test for type assertion and getter 'a'.
Minor fixes in docs for upcoming release
Make empty check empty, but not a length.
Added properties, to not inclusively check object properties on undefined.
Replace expresso -> mocha in docs.
Fix examples to work again
Merge branch 'master' of github.com:visionmedia/should.js into v2

Conflicts:
	Readme.md
Expose inspect function, that people can change options as they want.
Better support for custom descriptions, doc fixes
Merge branch 'nan-assertions' of https://github.com/ichernev/should.js into v2
Added Ininity assertion, fixed test for NaN
Merge branch 'patch-1' of https://github.com/ForbesLindesay/should.js into v2
Introduce assertions of each common type
Add alias for strict equality
Adding description back to the error message
More tests. Fix bug in empty.