Apache Olio workload revisited

Hello,
The current implementation of the Olio workload only supports the Ruby on Rails version of Apache Olio.

So I've decided to update it in order to let it work with both the PHP and Java version of Apache Olio.
You can select what version of Apache Olio to use by the new 'olio.incarnation' configuration parameter.

Also, I've tried to make the driver more compliant with the native (faban-driven) client
`org.apache.olio.workload.driver.UIDriver`
and to (hopefully) improve error checking.

See:
https://github.com/sguazt/rain-workload-toolkit/tree/wkl-olio/src/radlab/rain/workload/olio/README.md
for a description of the new configuration parameters.

Please, consider to merge this branch.

Best,

-- Marco