document /etc/resolver/ strategy on OS X
document /etc/resolver/ strategy on OS X

this should help make things clearer until we find a nice way of
automating it

refs #3

sneal/landrush,njam/landrush,phusion/landrush,vagrant-landrush/landrush,phinze/landrush,mheiges/landrush,vagrant-landrush/landrush,strzibny/landrush,LalatenduMohanty/landrush