Support reading properties file from HDFS

This change will allow CamusJob to read its properties file from HDFS as well.

Example usage: `-P hdfs:///user/erikvanoosten/camus/bin/data/camus.properties`
Other variants: `hdfs:/user/erikvanoosten/camus/bin/data/camus.properties` and `hdfs://hostname:port/user/erikvanoosten/camus/bin/data/camus.properties` should also work.

Note that `-P /opt/data/camus.properties` also still works.