Refactoring I.

- Revamp whole DB to Display flow
- Filter Pipeline, arbitrary filtering and sorting
- Binary tree arrays for faster lookup & manipulation
- DB: introducing custom functions
- DB scheme: split req into heap & cache
- cache written by GlassVPN only
- heap written by Main App only
- Introducing DB separation: DBCore, DBCommon, DBAppOnly
- Introducing DB data sources: TestDataSource, GroupedDomainDataSource, RecordingsDB, DomainFilter
- Background sync: Move entries from cache to heap and notify all observers
- GlassVPN: Binary tree filter lookup
- GlassVPN: Reusing prepared statement

main/Extensions/AlertSheet.swift

@@ -1,8 +1,8 @@
 import UIKit
 
 extension UIAlertController {
-	func presentIn(_ viewController: UIViewController?) {
-		viewController?.present(self, animated: true)
+	func presentIn(_ viewController: UIViewController) {
+		viewController.present(self, animated: true)
 	}
 }