Several changes to psphot and psphotStack
- Add function to compute the memory used by all of the sources
- Add function to log memory stats in psphotStack
- Don't load or psf match the convolved images into psphotStack unless they are needed.
This saves a lot of time if RADIAL_APERTURES are not enabled and we are measuring on the raw images
- Several improvements to the error handling in the Kron measurements. In particular the Mrf value
was being treated as positive when both the numerator and denomiator were negative. This is the cause
of many of the very large kron radius measurements. Set Mrf to NAN in these cases.
- Skip kron measurments for source if the previous Mrf measurement was NAN earlier in the process.
This saves memory by not expanding the source images when the kron measurements were actually going
to be skipped
- Remove the hack cut on fwhmMaj. Managing the kron radius measurements better fixes the memory explosion
that that helped to reduce.
