Require 'timecop' explicitly

This works around a problem with bundler's autorequires when not using
a standard Rails environment.
Don't depend on the environment in the test
Compare against an array instead of joining them into a string

No need to create a string out of them to get a good comparison
Extend RichMessage format to include other data

Uses new Regex to detect:

 @ context
 ~ project
 > tickler-date
 < due-date
 # tag (repeatable)
 * (starred)