Appneta (oboe) support

Add support for compiling in the latest oboe module for AppNeta TraceView.

[Product page](http://www.appneta.com/products/traceview/)
[Support page this PR is based on](https://support.tv.appneta.com/support/solutions/articles/86385-installing-nginx-instrumentation)

Untested, unfortunately, because I don't have access to an Ubuntu 12.04 box at the moment.