Refactor the ResourceFactory

[PsypherPunk]

Following on from the merging of #189, the ResourceFactory could use an overhaul.

Currently the code is a series of if statements:

if(urlOrPath.startsWith("http://"))
...
} else if(urlOrPath.startsWith("hdfs://") || urlOrPath.startsWith("s3://")

If we continue supporting more protocols this is going to get unwieldy. We should probably refactor the code better handle multiple Resource types.

[anjackson]

Java has a system for extensible URL protocol support, we could consider using it if necessary, or checking if these hooks have not already been written by others.

• http://stackoverflow.com/questions/26363573/registering-and-using-a-custom-java-net-url-protocol
• http://skife.org/java/url/library/2012/05/14/java_url_handlers.html