Put shiftadd in the pipeline and enhance

[StuartLittlefair]

Stu's shiftadd script (link to gist below) needs integrating into the pipeline, which needs a bit of work done:

• how to handle shifted images in the concept of MCCD and .hcm files (e.g what to do with data that falls in gaps between windows)?
• should we resample binned data onto 1x1 grid?
• put re-used code (e.g with joinup) into libraries to avoid duplication
• we could reject poor seeing data

We could also add a modified version folder that makes N images in phase bins rather than a single image.

[StuartLittlefair]

Gist of shiftadd script here

Gist of findOffs library here

[StuartLittlefair]

at the moment, new_wcs, Cleanup, ccd_info and ccd2arr have similar code in the pipeline that will need rationalising.