Make readme typografically better

Hey! I changed README.md a bit to make it look better in typographic meaning:
 * Replaced the hyphen with the en dash. Functions of en dash are described [in Wikipedia](http://en.wikipedia.org/wiki/Dash).
 * Removed the dot from the end of the title.
 * Decapitalized the “Basics” header.

Let’s make the language even more perfect!