New features

• Added a double-click to reset the cursor of position widgets (e.g. in image and text processes) to the center.

Fixes

• Fix crash when changing the port count of the Stereo Merger process.
• Fix that propagate was not enabled on the Stereo Merger process.
• Fix the order of messages between the start and end states, when pressing reinitialize.
• Fix alpha blending and opacity for images.
• Fix aspect ratio for images.
• Fix that the first frame of videos was skipped.
• Improve documentation
• Fix import of Format 0 MIDI files.