Refactor ccd data setup and addition of cosmic rays to test images
Refactor ccd data setup and addition of cosmic rays to test images

There were a number of smaller changes:
+ Cosmic ray flux increased to ensure all are caught given threshold
+ Change places where number of cosmic rays ways hard-wired to use number set at top of tests

pulsestaysconstant/ccdproc,crawfordsm/ccdproc,evertrol/ccdproc,indiajoe/ccdproc,mwcraig/ccdproc,astropy/ccdproc