Update install docs for conda opt deps [skip travis]
Update install docs for conda opt deps [skip travis]

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