add inverse to GenericModel
add inverse to GenericModel

stargaser/astropy,stargaser/astropy,saimn/astropy,larrybradley/astropy,StuartLittlefair/astropy,dhomeier/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,saimn/astropy,dhomeier/astropy,pllim/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,bsipocz/astropy,astropy/astropy,mhvk/astropy,MSeifert04/astropy,StuartLittlefair/astropy,astropy/astropy,bsipocz/astropy,stargaser/astropy,stargaser/astropy,MSeifert04/astropy,lpsinger/astropy,mhvk/astropy,dhomeier/astropy,mhvk/astropy,StuartLittlefair/astropy,saimn/astropy,astropy/astropy,pllim/astropy,bsipocz/astropy,astropy/astropy,pllim/astropy,StuartLittlefair/astropy,astropy/astropy,saimn/astropy,MSeifert04/astropy,lpsinger/astropy,saimn/astropy,lpsinger/astropy,pllim/astropy,lpsinger/astropy,aleksandr-bakanov/astropy,aleksandr-bakanov/astropy,mhvk/astropy,dhomeier/astropy,mhvk/astropy,larrybradley/astropy,dhomeier/astropy,StuartLittlefair/astropy,bsipocz/astropy,larrybradley/astropy,pllim/astropy,lpsinger/astropy,larrybradley/astropy