New Tests

• [done] modification tools
• [skipped, see below] insert image tool
• other tools that are not tested yet

Improvements

• [done] add option: exclude this test from "play all"
• add progress bar for play all tests

Stuff that couldn't be tested

• SplitIntoEqualParts: apply tool is not done with the close button as in other tools but with a separate button (close means cancel here). if the slot "slotSplit" from the current action can be called programmatically somehow, the test can be fixed with a that code.
• ZeroLengthDetection: ditto
• Image: needs native file dialog to get image file name