Redmine

Now that we have regex support for mail body delimiters, it makes sense to allow regex parsing for excluded attachment filenames as well.

The common case are email signatures including images. In many cases, the filenames include something like footer or signature, so regexes like the following proved to be quite useful for us at Planio:

smime.p7s,.+\.vcf,.*(footer|signature).*\.(gif|jpg|jpeg|png)

The attached patch series implements this feature.