Refs #12636. Add stored procedure. Add OnString::escapeSingleTickInHtml() incl. unit test. Next step: use  escapeSingleTickInHtml().

Refs #12636. Form: a) Single Tick encode for {{10.line.content::s}}, b) new encoding type 'single tick'. Part a implemented. Test missing.

Refs #12615. Implements silent HEIC/HEIF conversion to png. Write a note in realease notes, to install 'libheif-examples'.

Fixed a lot of unit tests, which did not passed on webwork16/crose/qfq. In test hardcoded 'http://xxxxxxxxxxxxxxxxxxxxxxxxxxxx/qfq/' makes trouble. CR did not find the place (qfq.json baseUrl tried) to adjust for phpUnit Tests.

Fixes #11265. Checked for BS and plain, active & disabled, with or without glyph. Code refactored to use more of Link class.

Implements #12085. Add doc and custom error message. Finalize directDownload notation. Add unit test.

Bug Fixes #11925. Form.parameter.downloadButton might contain now all parameter, incl. d, G, ... . KeyValueStringParser::explodeEscape() has been refactored. Function Link->paramPriority() has been renamed/rewritten to Link->paramPreparation(): double fire of explode() eliminated, code should be more efficient. Several new/enhanced unit tests.

Implements #6793. Source files for ZIP archives might now specified with a path/filename how they are called inside the ZIP.

Fixes #11509. Implement a) detection of broken 'split PDF to JPEG', b) fire 'pdf repair'. Also implement configuration von 'convert' and 'pdf2svg'