Many code changes to make everything work with Path and XmlInputFormat. Completes milestone 2.

The existing code works with Files. Hadoop works with [Paths](http://hadoop.apache.org/docs/r2.3.0/api/org/apache/hadoop/fs/Path.html) and [FileSystem](http://hadoop.apache.org/docs/r2.3.0/api/org/apache/hadoop/fs/FileSystem.html) which provide an abstraction over files and file systems. That is to say, Hadoop encapsulates the stuff about distributed or local files and files systems and lets us work with Paths and InputFormats. This pretty much sums up most of the stuff in the commits.

Other than that, I added the XmlInputFormat. I tested with run-extraction-test and everything works. DistRedirectsTest passes. I added some docs too.

Please note that I have taken care to make the commits in a specific sequence. If you make your way from commit 4b9745f to commit d08417f it'll be easier to understand what's going on.

Also, it's worth a mention that you'll need to clone https://github.com/nilesh-c/extraction-framework , switch to the **fromxml** branch and run `mvn install` before building this repo on this branch. I've made a PR to extraction-framework with the changes in **fromxml**.
> Can we enforce that somehow except only by mentioning it in the docs?

No, but I think that's ok. To make RichHadoopPath work, users have to import RichHadoopPath.wrapPath, and we can't 'force' them to have this import either. So I don't think it's a big deal if users have to have this import as well as an implicit Configuration value.

> But the compiler complains if wrapPathStub

Where? Could you post the full error message?

Does new Configuration() make sense at all? I don't know Hadoop, but I would guess that it has to configured with a few parameters.

I would guess that there should be one global Hadoop config object, and it has to be injected into every class and method that uses Hadoop. If DBpedia used something like Spring instead of its own clumsy configuration handling, that wouldn't be a problem. :-(