Adds a brief introduction to streams in the quickstart and the howto
Add more thanks
Thank Michael Hood
Explain how to match tags against expired events

It was a mystery to me that you could use periodically-expire to keep
tags on expired events until @bmhatfield explained about :keep-keys

This addition shows how to match expired events against tags for more
flexible event expiry logic
Merge pull request #215 from digital-science/howto-match-tags-on-expired-events

Explain how to match tags against expired events
thanks
Merge branch 'gh-pages' of github.com:aphyr/riemann into gh-pages
Merge branch 'add_more_thanks' of github.com:digital-science/riemann into digital-science-add_more_thanks

Conflicts:
	thanks.html
Merge branch 'rr-starting-with-streams' of github.com:rrees/riemann into rrees-rr-starting-with-streams

Conflicts:
	howto.html
Thank DCH
Thank lwf for timeouts on riemann tools