reuse last used color for newer text boxes (only if applied globally) + recolor text boxes on background changes (white text becomes black and black text becomes white (like for polygons))

fixed an issue where font family styles of a block with the same font family were lost when changing size

improved scrolling behavior (ensure visible) + fixed issues on drag and drop due to constantly regenerated thumbnails...

Fix massive memory leak in UBFFmpegVideoEncoderWorker.

This reverts commit 94140cbc.

fix massive memory leak in UBFFmpegVideoEncoderWorker::writeLatest{Video/Audio}Frame()
resoulting from freeing av_frame without freeing its data.
fix #222

This reverts commit 62a5ad33.

This reverts commit d5cf825c.

Use Appversion instead

This reverts commit f619e13d.

Revert "fixed an issue with quazip dependency on OSX + commit OpenBoard.pro changes for OSX (may need to be improved)"

This reverts commit bcf18abf.

According to docs AppVerName default value is made of AppName and AppVersion
http://www.jrsoftware.org/ishelp/index.php?topic=setup_appversion

fixed an issue with quazip dependency on OSX + commit OpenBoard.pro changes for OSX (may need to be improved)