TODO

[Stimulus]

- Take luminance into account.

[OpenGL]

- Control swap interval on non-wgl platforms.
- We have some shift problems displaying on window (.5 issue?).

[Real time]

- Increase thread priority.
- Check how to disable interrupts.

[EyeLink]

- Move to Qt5 QML.
- Change colours.
- Help menu.
- Move mouse on calibration.
- Parametrisable.
- Handle exit through window.
- Implement forced exit.
- Read images.