enhancements for email filter and attachment handling

[nnako]

see comments of the commits for further information.

Yes, and please get back to me about possibilities and "howto" of testing. Thanks.

[magopian]

Thanks a lot for those contributions. I'm currently on holidays, I'll check them asap and will get back to you!

What did you mean by "possibilities and howto of testing"?

[nnako]

Hi. I mean the "some checks have failed" message and what to do in order to get the checks run through. I'm new to this testing environment... maybe you have some pointers in order to save yourself some time testing and correcting.

[magopian]

Oh, it's the tests that ran on travis. If you click on "details", you'll be taken to the travis build, and from there you can see which tests have failed. If you want to run the tests locally (to try to reproduce the issues), you can do so by running make test.