Minor improvements and updates
- Add feedback when opening VeraCrypt Mounter (Closes: #16334).
- Improve consistency in Additional Software's accessibility
(Closes: #16110).
- Fix missing accessibility support when opening a browser from a
notification (Closes: #16475).
- Refresh ublock-origin patch to apply cleanly on top of 1.18.4+dfsg-1
(Closes: #16451)
- Upgrade intel-microcode to 3.20180807a.2~deb9u1.
Fixes CVE-2018-3615, CVE-2018-3620, CVE-2018-3646, CVE-2018-3639,
CVE-2018-3640, CVE-2017-5753, CVE-2017-5754.