Fixes possible npe

Thanks FindBugs
Adds rt.jar instructions for running tests
Adds documentation to the special resolutions

Both IGNORE_FIX and FIXED_BY_ANOTHER_FIX.  The distinction is subtle.
Adds test cases for SPP_USE_ISEMPTY

See #24
Adds tests for OCP

See #10.

This is just to see if it's possible.
Proof of concept OCP resolution

It's not pretty, but it seems to work in a few cases.
Cleans up OCP implementation

I can't access the bug from the visitor, so I can't do the custom labels
like I wanted to.

Fixes #10, for now.
Adds documentation to OCP_Resolution
Adds implementation for IsEmptyResolution

Fixes #24
Formatting