Updated Heroku

[Igal Koshevoy]

I've updated the with_heroku branch. It now includes the latest
Calagator changes and the documentation has been updates to match
Heroku's various changes, such as their database, "heroku run" and
such.

You can find further information about this at
https://github.com/calagator/calagator/blob/with_heroku/HEROKU.md

You can see a Calagator instance running on Heroku at
http://calagator-demo.heroku.com/

-igal