[Issues] Two issues: relative flux scaling & background subtraction

[Daniel Gruen]

Dear Astro-Wise community,

I'm new to AWE and have encountered two seemingly straightforward
requirements that I can't find a native solution for:

* I would like to have un-resampled background subtracted single
frames; background subtraction, however, only seems to be possible in
RegriddedFrames, not in ReducedScienceFrames
* rather than using a global photometric solution (which is good in
photometric nights but not necessarily in all nights) I would prefer
relative flux scaling of all frames going into a coadd (the way SCAMP
does it, i.e. by finding magnitude offsets for individual frames on a
matched catalog basis)

It's probably not too difficult to implement these two things, but
before I decide to do that it'd be great to know if anybody else has
perceived these to be missing and/or has found a clean solution within
the AWE framework.

Cheers,
Daniel