Got a simple test with the PRU working.

It runs on the robot, and can detect a drop.
Add a small build system.

This will easily compile the C code.
Made a system that can read from both sensors.

Right now, it waits for both triggers instead of firing with
just one. We'll probably have to use both PRU cores then.
Write code that can read drop sensor values.

The whole "having the PRU wait for the drop and notify the main
processor" thing wasn't really working out with libpruio, plus
it would entail some annoyingly messy python code, and it wasn't
scalable, so I've decided to take a slightly different strategy.
Correctly creates swig files.

This is done using a gyp action.
Remove unecessary dependencies from gyp file.

These were also causing the shared library build to fail.
Create a working SWIG module.

I can now get drop sensor values into python really fast using
the PRU. The build system also does all the SWIG work
automatically.
Integrate pru module into existing code.