UI: Add shortcut for larger movement steps in preview

Adds the ability to move a selected item 10 pixels in the preview when
holding shift while using the arrow keys, instead of going just 1 pixel
per step.

UI/window-basic-main.hpp

@@ -1120,6 +1120,10 @@ private slots:
 	void NudgeDown();
 	void NudgeLeft();
 	void NudgeRight();
+	void NudgeUpFar();
+	void NudgeDownFar();
+	void NudgeLeftFar();
+	void NudgeRightFar();
 
 	void OpenStudioProgramProjector();
 	void OpenPreviewProjector();