Rewrote README.md
Rewrote README.md

tomyeh/markd,srawlins/dart-markdown,srawlins/dart-markdown,dpeek/dart-markdown,srawlins/dart-markdown,dart-lang/markdown,johnpryan/dart-markdown,dart-lang/markdown,meflyup/markdown,tomyeh/markd,dart-lang/markdown,devoncarew/markd,dpeek/dart-markdown,tomyeh/markd,devoncarew/markd,meflyup/markdown