Fix & New Preview Feature

• vertexEdit (blue dot) allow to keep selectedVertices (selecteds small dot) while spinning & adding frame
• vertexEdit (blue dot) allow to move overred vertex (unselected big dot ) while spining & adding frame
• Preview & preview sliders allow to show previous  (transparent red) & next frames (tranparent blue) at a variable location (using translation dragg)
• keeping CTRL + DRAG CLICK while having a vertexEdit selected allow to draw lines
• Add frame skip the current frame while Replace frame keeps the user on the current frame

TOO MUCH TINGZ