Make classpath robustly platform independent

[paulschwarz]

The current implementation fails on Windows. This pull request solves the issue based on:

https://stackoverflow.com/a/17870390/2694806

[irobertson]

Doesn't compile - needs imports:

import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Paths;

[paulschwarz]

Oops, I'm sorry about that.

I've noticed another issue. My solution uses java.nio.file.Paths which is available from Java 1.7, but your project is set to 1.6.

I seem to be going down the rabbit hole here. I've also got tests failing with "Mockito can only mock visible & non-final classes."

[irobertson]

I would think that updating this to require java 1.8 would be completely reasonable at this point.

[paulschwarz]

Ignore and see #6 instead.

#6 does not completely replace this PR, but it's the foundation of moving to Java 1.8.