Update README.md

For those that want to live on the bleeding edge and aren't familiar with how to build it like me.
Merge pull request #114 from Krayzk9s/patch-1

Update README.md
Merge branch 'master' of https://github.com/koush/ion

# By Kurt Zimmer
# Via Koushik Dutta (1) and Kurt Zimmer (1)
* 'master' of https://github.com/koush/ion:
  Update README.md