Add ability to create a custom coordinate transformation graph
Add ability to create a custom coordinate transformation graph

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