Process Excellence Network

Invalid date

Adds Notifications feature:
- List screen.
- Displaying new notifications.
- Sending notifications on new activity or comment.
- Link detection in notifications.

Changes Sign-up flow:
- Adds LinkedIn integration.
- Fixes whitespaces bug.

Fixes bugs:
- Crashes.
- Navigating twice to some of the screens.
- Changing user avatar.
- Notification date.
- Missing privacy policy link.

Changes styles of some of the screens.