Update CHANGELOG.md

This change updates the Changelog file with a brief enumeration of new
features and changes in 2.0.0 development version.

release version 1.3.5

version 1.3.4

Merge branch 'dev'

release 1.3.2

napiprojekt3 support

new version release

version 1.1.13

version 1.1.12

- fps detection using ffmpeg added
- corrections to subotage
- Abbreviations support added - you can add any custom string between the filename and it's extension

added support to download subtitles in a selected language