Trim spaces and other invalid characters from Twitter usernames.

As per Twitter's specification:
https://support.twitter.com/articles/101299-why-can-t-i-register-certain-usernames
Allow one day events
Added bootstrap
Merge pull request #41 from geeksoflondon/38_bootstrap

Added bootstrap
Merge pull request #40 from geeksoflondon/38_improve_validations

38 improve validations
added Eventbrite::Importer for attendees of a specific event

most basic attendee though (no validations for tshirt and diet). Also still need to add tickets for the specific event
Merge branch 'refs/heads/master' into 11_import_event_brite

Conflicts:
	app/models/attendee.rb