Minor maintenance release.

Fixes crash in Web Interface search.
Global server search functionality restored.
Mediainfo.dll 19.04 can be used.

Bugs fixed:

- crash when loading emulecollections
- UPnP crash in Windows XP
- Web Interface regression in Search
- e-mail notifications were broken due to bugs in ATL
- regression in Scheduler's options
- crash when deleting a part file while it was hashing

Allow mediainfo.dll 18.12

Maintenance release.

Fixed bugs and regressions.
Web Interface: added certificate generation and search for collections.
Minor improvements in chat (Messages).

Preparing for the release.

.: Changed: version check and online help will use HTTPS
.: Changed: Content-DB searches will use HTTPS
.: Fixed: Web Server link in network info dialog adjusted for HTTP/HTTPS

.: Fixed: minimize to tray after display scaling change

.: Fixed: checks for null pointers in Kademlia code
.: Fixed: after initial bootstrap KAD contacts list stopped updating (regression)
.: Changed: expanded tooltip to 128 characters
.: Changed: reuse source exchange socket for downloading (thanks to Enig123)
.: Changed: minor dialogs optimizations
.: Removed: unused HyperTextCtrl.* files