Inspections for DrawGizmo callback parameters

[citizenmatt]

Add inspections to ensure callback methods marked with the DrawGizmo attribute are defined with the correct parameters, e.g.

[DrawGizmo (GizmoType.Selected | GizmoType.Active)]
static void DrawGizmoForMyScript (MyScript scr, GizmoType gizmoType)

This must have two parameters, one object that is the target, and the second is GizmoType. The inspection should verify the type of the target object. (What is this type? MonoBehaviour? Component?)

[citizenmatt]

Are there any other callback methods like this? Create new issues for each new callback type.

[JurjenBiewenga]

I'd like to pick this issue up