Update Changelog.txt.

[ci skip]
Keep source file TTML time code format per default
Some minor performance improvements
Formatting.

[ci skip]
Minor refact regarding StringComparison.OrdinalIgnoreCase - thx alphaproject :)
Minor refact
Fixed batch convert to show better progress + faster
SE 3.4.4
Formatting.

[ci skip]
Fixed resource leak in batch convert
Update cs-CZ.xml
Merge pull request #344 from Trottel/patch-8

Update cs-CZ.xml
Fix  #343 - Export to images now uses Pen LineJoin = Round - thx rebawest :)
Merge branch 'master' of https://github.com/SubtitleEdit/subtitleedit
Correct version number in Slovenian translation...
Fixed bug in Blue-ray reading due to bad refactoring
Trying to fix possible crash
Added some read support for format Ayato - thx Jack :)
Fixed bug regarding "Remove dash in beginning of lines" - thx Robert :)
Some fixes for Ayato format