Convert interact tests to new testing infrastructure.

[itsjohncs]

This is fortunately fairly trivial, but might take a little bit of time. I want to change the tests over from using the standard library's unittest module to pytest. In addition, I want to set up Tox to test it running under Python 2.6 and 2.7 because both are supported.

[itsjohncs]

The old unit tests are hardly useful tests... This became a bit harder.

[itsjohncs]

Making good test files will be a great way to do make the interact tests scalable and useful.

{}
0:#include <iostream>
0:
0:using namespace std;
0:
0:int main() {
1:    cout << "Hello world" << endl;
1:    return 0
0:}

The first line is a dictionary (font-matter). Every line begins with a number which helps determine the indentation level of that line. The rest is as expected. This should give us the ability to test all of interacts functionality in a fairly straightforward way.

I want to get more work done on Galah's core but I'll work on this more another time.