Speech class modified, to keep track of external persons' speeches
Initial time is optional
small corrections to admin and views, after modifications to the Speech class
newsletter targets selection improved: nlsend command now does not block
registration urls override added back to settings
sitting extends now TimeStampedModel, it's needed to keep track of new sittings, as imported; the task to check for newly imported items has been renamed to new_items_alert
incomplete text in registration form removed
new_items_alert task implemented
Merge branch 'dev' of https://github.com/openpolis/open_municipio into dev-senigallia

Conflicts:
	open_municipio/acts/models.py