threshold

Changes:

• Image binarization using EdgeDiv (combine EdgePlus & BlurDiv) local/global thresholding method (@zvezdochiot)
• AppImage support for Linux (@lightsilverberryfox)

Additionally: build of Qt5 by @plzombie

• qt5_win64 - build by @plzombie (see OS: Windows? #1 (comment)).

Additionally: Mod bg

• bg - added new zones: ForeGround and BackGrount (ScanTailor-Advanced#50).

Qt6

Changelog

• Negative margins
• Qt6
• Updated Polish translation
• fix for openGL (wayland)

Additionally: Mod epbd

• epbd - added new threshold methods: EdgePlus and BlurDiv (ScanTailor-Advanced#48, ScanTailor-Advanced#47).
• qt5_win64_epdb - build by @plzombie (download vc runtime here).

Additionally: Mod epbdta

• epbdta - added thresholdAdjustment for all threshold (ScanTailor-Advanced#48, ScanTailor-Advanced#59).
• qt5_win64_epdbta - build by @plzombie (download vc runtime here).

Additionally: Mod epbdtaed

• epbdtaed - added new threshold method: EdgeDiv (EdgePlus & BlurDiv) (ScanTailor-Advanced#48, ScanTailor-Advanced#8).