New features

• It is now possible to generate a 2D spline from an arbitrary set of parametric equations.
  Right-click on the spline and press "generate curve" to do so.

• Also, the 2D spline edition has been improved greatly with the ability to zoom, recenter, etc.

• Allow to create Mapper devices that will run a function at a regular interval, in order to have periodic triggering or just any kind of advanced behaviour one could want.
  Here is an example: https://github.com/ossia/score-user-library/blob/master/Devices/Mapper/Timer.qml

Bugfixes & refactors

• Fix domains not being reloaded properly
• Rework graphics pipeline to prepare for more advanced graphics processes
• Fix build on Qt 5.9 & 5.12
• Fix some MIDI issues