Added starting Redis step to 'How to get it going' instructions

README hadn't been updated since introduction of Redis.
Updating _.detect() to _.find()

.find being the new preferred name per http://underscorejs.org/
Changed variable declarations to match style guide
Clean up spacing and indentation
Remove duplicate definition of checkName function (first defined on line 631)
Adding a couple comments to the checkName function to explain the allowed character ranges
Increase username character limit to 12 characters.
Allow a few more special characters in usernames

The following additional characters are now allowed: space, underscore, parantheses, caret (^).
Display error Create New Character form when username is rejected by sanitizer

Previously, attempting to create the user failed silently. This partially fixes #121, but see the discussion.