Use Unicode directional formatting codes in README.md

It's not github that mangles the code samples in the README—the mix of left-to-right and right-to-left text is enough to confuse a lot of software, and in this case it's the standard Unicode bidirectional algorithm that isn't smart enough to figure out what you wanted. Basically, I think it treats the parentheses and other punctuation as left-to-right by default.

However, Unicode offers a way to specify explicitly that a particular paragraph or word is intended as an island of right-to-left text in an enclosing left-to-right document. This patch does so for a few bits of Arabic in your README.md.

More information here: http://www.unicode.org/reports/tr9/#Directional_Formatting_Codes