[TASK] Refactor code

Change in sending newsletter logic. Instead of rendering newsletter content
each time for every recipient it will be rendered only once and set it to
newsletter body.

Change-Id: Ic252d05375abcd5e0b4b2e5024fb77a786602293
[TASK] Change in delete recipients

If user is subclass of Person from newsletter then set subscribedToNewsletter
to FALSE and update it otherwise user will be get deleted.
Merge branch 'master' of github.com:lelesys/Lelesys.Plugin.Newsletter

Conflicts:
	Migrations/Mysql/Version20140429113440.php