Crash fixes

• [Duplicate] Fixed: Undoing (Ctrl Z) duplication of a character led to a crash
  
• [Copy Paste Key] Fixed: Copy/Pasting a pose from a scene to another one led to a crash
  

Bug fixes

• [IK/RF] Fixed: In not-current character, IK/RF (which are not displayed) were still pickable
  
• [Space Switching] In Transform Dialog, Space Switching checkbox is now considered
  
• [Curveboard] Fixed: Last key tangents couldn't be edited (loop key tangents should still be manipulated through the 1st key)
  
• [Camera] Fixed: Scale was not effective anymore in the view when Spinner Scale button was set