xF2 Add-on AndyB Insert attachment all 2.0

Insert attachment all v2.0 changes:

Now inserts thumbnails inline.

Insert attachment all v1.90 changes:

Fixed issue if alt reference contains a closing bracket.

Insert attachment all v1.7 changes:

Added 'Insert thumbnail' to options page.

Insert attachment all v1.6 changes:

Added code to prevent running add-on if ._xfImport is contained in any posts.