ticket:227 MassEmail model. Initial commil

[new] A model
[new] Admin Area
ticket:227 Merged with master
ticket:227 Merge branch 't227_massemail_model' of https://github.com/42cc/mass_post_office into t227_massemail_model

Conflicts:
	admin.py
	models.py
ticket:227 MassEmail status field changes
Merge branch 'master' into t227_massemail_model
fixed MassEmailAdmin.status
ticket:227 Tests were implemented
minor tuning of admin.py
Merge branch 't227_massemail_model'
mass emails can now be sent from admin interface