Prepare for newrelic 3.0.

NR related scripts and daemon will only run if env var
NEW_RELIC_LICENSE_KEY is defined and that the 3.0 package specific
NEWRELIC_VERSION file exists in /app/local.
Newrelic version: 3.1.5.137.

Fixed: #8.
Incompatible change in Newrelic 3.0.

Please update your copy of 04_newrelic.ini from the sample provided.
Tweaked stock newrelic.cfg.