Internal data check 2.0

Internal data check v2.0 changes:

Now using abstracted Flysystem.

Internal data check v1.9 changes:

Added Data ID column in results page.

Internal data check v1.8 changes:

Added support for audio and video attachments.

Internal data check v1.7 changes:

Updated Missing file list.

Internal data check v1.6 changes:

Now checks all attachment content types.

Internal data check v1.5 changes:

Compatible XF 2.x versions: 2.3

Internal data check v1.4 changes:

Added Data ID to results page.

Internal data check v1.3 changes:

Added count totals to results page.

Internal data check v1.2 changes:

Checks are now limited to image attachments in posts.

Internal data check v1.1 changes:

Updated description and icon.jpg file.