Fixed issue with web sessions and CloudFlare handler
Refactored NZBGet host:post required pattern, resolves issues with saving config settings
Refactored frequency change functions to use `reschedule_job` apscheduler function, resolves issues with frequency not being updated correctly
Fixed issue for full backlog searches not running if no show_id is passed

Refactored requirements.txt to replace package hachoir3 with hachoir, hachoir3 was removed from PyPi.

attempting to grab images that may result in a HTTP 404 error code.

Adding in MySQL functionality for larger databases that may perform
poorly using SQLite.

Refactored how show statistics are gathered.

Refactored web views and handler code.

Refactored database upgrade functions to use sqlalchemy-migrate

Updated cfscape to 1.9.7

Updated keycloak client requirement version.

Added multiple methods to help install requirements.txt
Updating fails if installing/updating requirements fails