All Tomorrow's Parties example -- first checkin
WIP
update to use loginButtons helper
Meteor._autorun -> Meteor.autorun
Only publish parties that the user should see
Bump version number for 0.5.0.
Restrict visibility of private parties.

While doing so, refactored rsvps to now be an array on party rather than a separate collection.
parties: complete write restictions
parties: limit string lengths
parties: unselected parties are transparent
parties: add a placeholder background map image
parties: ux doesn't allow posting a party when logged out
fix documentation order
carry text along w/ api box.
Clarified when reactivity works

After reading the Reactivity section for the first time,
I was under the slight impression that a reactive context would
be sufficient for triggering changes. E.g. if the name in the
fragment example were set not from Session, but from a global,
it could be surmised that the HTML fragment would still be
automatically updated if the global variable changed.

This small patch tries to make it clearer that reactivity requires
*both* a reactive context and a reactive data source.
Use better_markdown throughout
Fix run-on sentence
parties: can create private parties
parties: fix access control check on rsvp method
invitation dialog
update map style