Fixes a slight bug in the Parameter.validator property.  On Python 2 if you don't explicitly pass a class to MethodType the repr of the resulting bound method doesn't know what class the method is bound to (but it still seems to work).  The test I added doesn't actually test this issue, since calling the bound method still works.  But it was still worth adding.
Fixes a slight bug in the Parameter.validator property.  On Python 2 if you don't explicitly pass a class to MethodType the repr of the resulting bound method doesn't know what class the method is bound to (but it still seems to work).  The test I added doesn't actually test this issue, since calling the bound method still works.  But it was still worth adding.

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