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**.
Also, an implicit conversion method doesn't have to be a static method that you import. It can also be an instance method. For example, you could have a class ```HadoopPathWrapper``` which has a Hadoop configuration as an instance field. It's only job is to wrap ```Path``` objects into ```RichHadoopPath``` objects. It has a method ```wrapPath``` that works just like this method but doesn't have an implicit parameter, because it uses the instance field. I don't remember the specifics, but I think it's not hard to use the instance method as the implicit conversion.

Or maybe even better, call the method ```apply``` and use the ```HadoopPathWrapper``` object itself as the conversion function.