Have the doctest plus module skip/ignore any modules that raise an ImportError when trying to import it to look for tests.  In particular this is needed to skip modules that require astropy_helpers, like some of the setup_package.py modules.  This seems like reasonable-enough behavior anyway--if some actual problem is causing ImportErrors in some modules that will hopefully be picked up by the normal unit tests as well.
Have the doctest plus module skip/ignore any modules that raise an ImportError when trying to import it to look for tests.  In particular this is needed to skip modules that require astropy_helpers, like some of the setup_package.py modules.  This seems like reasonable-enough behavior anyway--if some actual problem is causing ImportErrors in some modules that will hopefully be picked up by the normal unit tests as well.

lpsinger/astropy,kelle/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,larrybradley/astropy,tbabej/astropy,astropy/astropy,dhomeier/astropy,stargaser/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,stargaser/astropy,StuartLittlefair/astropy,joergdietrich/astropy,joergdietrich/astropy,mhvk/astropy,MSeifert04/astropy,joergdietrich/astropy,kelle/astropy,DougBurke/astropy,larrybradley/astropy,astropy/astropy,pllim/astropy,saimn/astropy,pllim/astropy,lpsinger/astropy,funbaker/astropy,AustereCuriosity/astropy,kelle/astropy,joergdietrich/astropy,tbabej/astropy,bsipocz/astropy,AustereCuriosity/astropy,larrybradley/astropy,saimn/astropy,AustereCuriosity/astropy,tbabej/astropy,mhvk/astropy,aleksandr-bakanov/astropy,funbaker/astropy,kelle/astropy,dhomeier/astropy,larrybradley/astropy,mhvk/astropy,stargaser/astropy,astropy/astropy,DougBurke/astropy,AustereCuriosity/astropy,pllim/astropy,StuartLittlefair/astropy,dhomeier/astropy,saimn/astropy,tbabej/astropy,astropy/astropy,tbabej/astropy,kelle/astropy,funbaker/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,dhomeier/astropy,bsipocz/astropy,mhvk/astropy,dhomeier/astropy,funbaker/astropy,saimn/astropy,saimn/astropy,MSeifert04/astropy,bsipocz/astropy,lpsinger/astropy,pllim/astropy,astropy/astropy,pllim/astropy,stargaser/astropy,mhvk/astropy,bsipocz/astropy,MSeifert04/astropy,lpsinger/astropy,DougBurke/astropy,DougBurke/astropy,StuartLittlefair/astropy,joergdietrich/astropy,lpsinger/astropy,AustereCuriosity/astropy,MSeifert04/astropy