* Refactored updating chapter metadata from ComicInfo into the Scan loop. This let's us avoid an additional N file reads (expensive) in the metadata service, as we already have to read them in the scan loop.
* Refactored Series level metadata aggregation into the scan loop. This allows for the batching of DB updates to be much smaller, thus faster without much overhead of GC.
* Refactored some of the code for ProcessFile to remove a few redundant if statements
* Refactored all files to have Interfaces within the same file. Started moving over to file-scoped namespaces.
* Refactored common methods for getting underlying file's cover, pages, and extracting into 1 interface.
* More refactoring around removing dependence on explicit filetype testing for getting information.
* Code is buildable, tests are broken. Huge refactor (not completed) which makes most of DirectoryService testable with a mock filesystem (and thus the services that utilize it).
* Finished porting DirectoryService to use mocked filesystem implementation.
* Added a null check
* Added a null check
* Finished all unit tests for DirectoryService.
* Some misc cleanup on the code
* Fixed up some bugs from refactoring scan loop.
* Implemented CleanupService testing and refactored more of DirectoryService to be non-static.
Fixed a bug where cover file cleanup wasn't properly finding files due to a regex bug.
* Fixed an issue in CleanupBackup() where we weren't properly selecting database files older than 30 days. Finished CleanupService Tests.
* Refactored Flatten and RemoveNonImages to directory service to allow CacheService to be testable.
* Finally have CacheService tested. Rewrote GetCachedPagePath() to be much more straightforward & performant.
* Updated DefaultParserTests.cs to contain all existing tests and follow new test layout format.
* All tests fixed up
