Some updates for newer jQuery. (Sorry about the reformat)

[sam159]

Added error handling to progress ajax.
Updated for jQuery 1.9+ where $.browser has been removed.

[clemensg]

@sam159 It's very hard to see the real differences in such a commit. Reformatting should always be done extra, if necessary.

Also, checking for Webkit or Safari alone is a bad idea, because it matches Chrome too!
Instead we should change $.browser.safari to something like: /safari/.test(navigator.userAgent.toLowerCase()) && !/chrome/.test(navigator.userAgent.toLowerCase())

And regarding error handling I'd prefer the solution from PR #10.

@drogus In case @sam159 does not respond: Should I create a new PR or could you please change the $.browser.safari line? Thanks.