Usability fixes

[ghost]

• The first commit adds a simple build.js file so that Smoosh can be installed locally in the repository's root directory.
• The second commit removes the browser sniffs and fixes opacity animation in Internet Explorer, which was completely broken. The patch is based on work by @kangax, who added cross-browser support for opacity animation to his fork of Emile.

I haven't added unit tests for the opacity fix yet, but I've successfully tried it with a modified version of this test for Emile. I'm still thinking of the best way to write a test for this change. Also, I noticed that the "Colors" unit test module fails completely in IE. I'll submit another pull request once I deduce what the problem is.

[ded]

i've got this working in IE now (some other weird crazy gotchas in the color morphing and bounce tweens)

[ghost]

Great!

[jdalton]

@ded \o/ for the added IE support. I'm still confused as to why you've chosen to keep the IE UA sniff. Could you provide a little insight into why you've kept the UA sniff in a few of your projects?