Clarify how the host resolver works on Mac OS X
Clarify how the host resolver works on Mac OS X

Added a more explicit description of the `/etc/resolver` setup.

Closes #111

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