Improved memory usage from database calls.
Misc code cleanup.

Fixed issues with episode searches and episode search retries
Fixed issue with data retrieval from database files

Added backdrop for history view
Added opacity style to views with backdrops

Case-insensitive sorting fixed for shows view

Migrated misc css classes to bootstrap 4

Migrated manage queues view

Refactored manual post-processing view
Refactored edit show view
Refactored main layout
Refactored config layout

Upgraded to Bootstrap 4.x
Merged misc icons into core icon pack

Added ability to unlink account from app
Fixed issue with scheduler view and empty show runtime
Replaced all no16 and yes16 with font awesome equivalents

Added ability to manually set external upnp port number

Added ability to download unverified torrent magnet links
Fixed issues for access data retrieved from SR API endpoints

Changelog now popups up after updates only once