Viewer: added a setting to disable auto-wipe toggling when connecting
viewer inputs. When checked, behaviour will stay the same as it was,
i.e: changing a connection will connect to the input B, whereas when
unchecked the input A connection will be changed and the wipe will not
show up, unless explicitly brought up by the user.
Merge branch 'workshop' of github.com:MrKepzie/Natron into workshop