adding new email(Threading based) and welcome email.
Basic email sending is now functional
Added 2 days timeout for keys and links for labels
Added testing code
Merge branch 'master' into email
using redis.multi() to store data into redis
Improved email subject line and UI
fixed few bugs.
enabling threader for all rooms
Fixed bugs related to subject line of email and removed testing code
	* config.email.debug can be used for debuging
Merge branch 'email'