There are certain situations in which getAuth() may want to be overridden by a
backend for performance reasons. The attached patch converts getAuth() into a
virtual backend function. The default is for no change in functionality. In my
tests this leads to very significant performance improvements under certain
situations

fixes PowerDNS/pdns#581
Merge branch 'master' into backend-getauth
kill getAuth function that keeps reappearing
comment changes
Merge branch 'master' into backend-getauth
remove DEBUGLOG debug code
Merge pull request #1130 from mzealey/backend-getauth

There are certain situations in which getAuth() may want to be overridde...