Appion

With MRC image stack and Xmipp Spider particle file data in the same orientation. The euler convention turns out to be the same once mirror in Xmipp is converted. However, the xy shift applied are different in the two packages. 3DEM convention did not include definition of the shift. Using EMX tentative convention (consistent with Xmipp), we will store in the database in that way.

This means the result of Frealign refinement need to be converted to what will be saved in the database. Reversed conversion is also needed when converted back.