Add benchmark

[allevo]

Add some tests to show how much the performance improves/degrees applying multiple time flatstr.

The result is not so obvious!

[davidmarkclements]

nice can you please update readme with results

[allevo]

I'd like to create a little graph. Could you suggest me a nice library?

[davidmarkclements]

I actually don't know of "the best" tool or approach – obviously there's R but that's probably far more than needed. At the other end of the spectrum, creating graphs in Google Spreadsheets is a breeze – but word of warning, the image export of Google spreadsheets is really poor quality (I've done screenshots of them instead, much better).

Then there's gnuplot... or d3.js ..

I don't know man – dealers choice – /cc @mcollina

[mcollina]

I don't know really, I used R, d3 and even did it by hand with Omnigraffle in the past.