-- fixing some typos and grammar snafus in README

Fixing 2 typo and grammar snafus in README. Also, the permalinks in the README are broken. Can't find new locations for things like [Schema For Clojurescript Data Shape Declaration And Validation](http://blog.getprismatic.com/blog/2013/9/4/schema-for-clojurescript-data-shape-declaration-and-validation).