Gamma corrections and linear contrast adjustment.

code from CanvasComplex.

First version of Primawera

See merge request !10

feat(canvas3d): synchronize other views with the main view.

See merge request xpetrus/primawera-test!9

Since sometimes numpy creates a view instead of copying the data, it was possible to use this behaviour to change the raw data inside the object. I was not able to find the exact condition when this happens as it seems to happen randomly.

It was not possible to apply LUT after a filter.

When LUT is active, some filters become invisible.

feat: Attaching with IPython event loop.

See merge request xpetrus/primawera-test!8

The app now checks if it is already running inside an QApplication instance. In which case it does not start the `exec_` function. That means that IPython can attach to Qt's event loop, hence creating the main application does not block the interactive shell.