Restructure source files

Closes #146

See merge request !331

- no split between include/src anymore
- more directories grouping files by their function
- CMakeLists.txt setup to support file lists in each subdir

Create Edit Menu with undo/redo

Closes #463

See merge request !325

- Rename "Delete" menu item to "Edit"
- Move it next to "File"
- Add undo/redo actions to the menu

Add "Split trajectory" to context menu

Closes #462

See merge request !330

Resolve "Make PersonStorage::Direction usage consistent"

Closes #465

See merge request !326

fix for jittering

See merge request !322

Resolve "TrackPerson inserting with interpolation not working as expected"

Closes #466

See merge request !327

update copyright year

See merge request !328

Resolve "Add script for updating the year in the copyright header"

Closes #226

See merge request !324

Add dnn to opencv

See merge request !323

Resolve "Error message: cx cy not valid any more"

See merge request !319

Resolve "Pipeline failure"

Closes #457

See merge request !320

Enable loading in videos from Hermes-Experiments

See merge request !308

Undo redo

See merge request !316

- Create a CircularStack
- Use said stack for creating an undo and redo stack using Memento
- Apply the stack via keyboard shortcuts

Resolve "Make sure that every slider also gets a spinbox"

Closes #329

See merge request !310

Move variable moveDir into loop to prevent accumulation effects

Closes #444

See merge request !317

Error on export with autocorrect perspective view with "only export"
Move variable moveDir into loop to prevent accumulation effects

Always use whole image as boundingRect fo Coord

Closes #313

See merge request !315

- Always use whole image as boundingRect fo CoordItem
  -> Fix for wrong/small bounding rect before

Merge branch '427-extrinsic-calibration-does-not-calculate-correct-reprojection-error' into 'master'

Resolve "Extrinsic calibration does not calculate correct reprojection error"

Closes #427

See merge request !313

Due to a mistake in !267, the error of the extrinsic calibration was calculated using the old calibration (i.e. all zeros on a new project). This leads to a terrible error and thusly to the rejection of the new calibration.

This commit fixes this by using the new extrinsic parameters to calculate the reprojection error. It also adds some simple regression tests for the extrinsic calibration to catch such mistakes earlier in the future.

Resolve "Make Slider only scrollable when clicking on them"

Closes #333

See merge request !305

Add PGroupBox

Closes #277

See merge request !307

- Add PGroupBox
  Custom GroupBox with option to "gray out" its content
- Change all GrouBoxes in calibration tab to PGroupBox

Merge branch '428-wrong-error-values-displayed-in-average-extrinsic-calibration-column' into 'master'

Resolve "Wrong error values displayed in 'average' extrinsic calibration column"

Closes #428

See merge request !314

Load AVG_PH instead of SUM_PH etc., since they are saved as such in the pet file