Update README.md

Came across your library; I'm sure you didn't intend to cause any offense, but the second sentence in your README contains two all-too-common and [hurtful](http://www.unwomen.org/en/news/stories/2011/7/countering-gender-discrimination-and-negative-gender-stereotypes-effective-policy-responses) attacks used by some to belittle and marginalize women. This PR removes that sentence and fixes the grammar in the first.