Set notification date to not NULL
Use the email address of the receiver as their username
Do not use gltime anymore
Implement basic unittest for tip testing
Merge remote-tracking branch 'origin/refactor-db' into refactor-db

* origin/refactor-db:
  ReceiverFile table is generated, and Receiver.id referece added
  checksum fileprocess
  rewriting plugin for email's sake
  added sqlite constraints for markers
  merging notification email from feature/email
  asyncronous email

Conflicts:
	globaleaks/db/sqlite.sql