update versions.json
update package.js for Meteor 0.9.1
fix waitlist onInvalidate logic

See:
https://github.com/EventedMind/iron-router/commit/69222246194fb630996fdb988335fed208e4caf4#commitcomment-7565234
update changelog
fix package.js to use METEOR vs METEOR-CORE in versionsFrom
fix versions for blaze-preview
oops bump iron:layout version too
Merge pull request #1 from EventedMind/devel

Merge upstream changes