add expiration date and cleanup

- add expiration time to activity
- fix discrepancies caused by earlier minor changes on master
- remove unnecessary filter
add list of changes to activity

activity stream and add activity simulation now allows for a list of
changes to be added to database with each activity
remove expiration date
Merge pull request #8 from reebalazs/activity_stream

Activity stream - merging so that next activity_stream branch can utilize changes made to authService on master