Upgrade dependencies
Remove Contributing from README
Bump version to 0.3.0
Update deps
Add manpages and update README
Only send notifications for unread entries

* Don't request read entries, in case someone recently added a new feed
  and marked all as read
Convert html content to plaintext
Add Makefile + better versioning
Fix email date header not being set

Refactored email notification to use connection.
Fix null-pointer exception
Add HTML option for email and webhook
Add Gotify notifier
Ensure at least one notifier and add list command
Allow missing config sections
Add email notifier
Refactor for multiple configs, centralize test
Refactor to allow multiple notification targets