Delete modular .gitignores

With the directory structure in flux prior to migrating towards a
setuptools based build system, the paths referenced in different
.gitignore files have a tendency to get out-of-date quickly.

For this reason, this commit removes the more modular, per-directory
.gitignore files (only one of these existed, in the test/data
directory).  So this commit removes this file and moves its
'excludes' into the main .gitignore.

Issue #5
Create module from disparate tests.

The tests were located in the 'test/' directory (which makes sense),
but weren't being recognized by the prototype setup.py that I've been
iterating on.  After reading up on Python conventions, it turns out
that most Python entities are supposed to live in 'packages'.  Unlike
directories in Java, which are considered packages implicitly, a Python
package requires an __init__.py file in the directory.

I knew this, but had learned it after creating 'test/' initially, and
hadn't been prompted to make this directory a package until now.

This commit makes the test/ directory a package by adding this
__init__.py file.

Issue #5