Minor fixes and behavioral changes:
• Opens options page if nothing has been configured.
• Shows an error when you open your routine but have no pages for the day.
• Error popup now properly displays text and closes when options page is opened.

Added a few feature requests from users:
* Open pages as pinned tabs
* More specificity for automatically closed tabs
* Avoid re-opening pages that have already been opened

Also some internal refactoring to make future modifications easier.

Added a few URL validation checks to avoid attempting to open invalid URLs, and to alert the user when a URL fails to open.