Newreg continued

Continuation of !249 (merged)

Closes #750 (closed)

Closes #254 (closed)

• improve 2-3 stars speed by computing H matrices right after seqpsfs
• add rigid transform in 2-3 stars registration
• implement -framing= option in seqapplyreg
• -selected may be added to register as well
• in the Plot tab, add Xcenter and Ycenter data to existing registration: compute them from the H matrix using the intrisic matrix of the reference frame. This should enable to select the best framing, irrespective of meridian flip
• in the frame display, add a box showing the framing wrt to reference frame
• -framing=cog option should try to automatically define the best "framed" image, i.e. the one which has its center closest to sequence cog (only accounting for selected images)
• -framing=max option should determine the bounding box of all images of the stack
• -framing=min option should determine the enclosed common area to all images of the stack
• check the output sequence size accounting for framing option in applyreg