* Removed comment_type 'updated'
* New doctype activity log
* Moved feed.py to activity_log
* Updated feed gets stored in activity_log
* Activity page fetches feed from activity_log
* feed match condition change
* modified
* modified hooks.py
* modified sessions.py
* patch added
* naming in patch
* moved login, logout feed to activity_log
* changes in auth.py, hooks.py
* deleted doctype authentication_log and added test cases
* added utils.py in core
* moved some methods from communication.py to utils.py
