DABstar version 4.2.0 for Windows

What's Changed

• The code base handles now the usage of the Osmocom RtlSdr driver but the improved driver from @old-dab is recommended.
  See Link1 / Link2.
• @old-dab analyzed the corrupted DLF Journaline and this AppImage includes a workaround for that problem.
• Audio peak level meter works more fluently now.
• Takeover a fix for the ETI generator from Qt-DAB.
• Minor UI adaptions and some code refactoring.

Full Changelog: v4.1.0...v4.2.0

The Linux version is here: https://github.com/tomneda/DABstar/releases/tag/V4.2.0