Added Quantity to Angle conversion test cases.
Added Quantity to Angle conversion test cases.

Angle(1.0*u.deg) should be OK.
Angle(1.0*u.meter) should raise a UnitsError.
Angle(1.0*u.hour) should be converted to Angle(1.0, unit=u.hourangle).

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