Add rails 4.1 mail preview
Upgrade pry-byebug to fix "interface" errors
Update unicorn config to run in local development
Update docs
Update dev logging config to support unicorn
Update mail settings

Note: url_for is still broken in Rails 4.1.0.beta1
in ActionMailer. Waiting for the next release 
before emails will work again.
Update gems
Revert "Upgrade pry-byebug to fix "interface" errors"

This reverts commit e11b64c12113dcea008dd45af07b3682c45ddbfc.

pry-byebug 1.3.0 is not ready for prime time.
https://github.com/deivid-rodriguez/pry-byebug/issues/22