What is this, again?
Started on a helper script to actually run tests.

The idea is that the testrunner.sh script is used to run "drivers", i.e. python-lzjb and the C driver.

This will generate compressed files from the two engines, which we will later compare. Or something.
Consistency. We can have it.
Simplified size-encoding.
Use shift rather than math.floor() and division.

I suspect that the math.floor() business was a JavaScript-ism, which we can live without.
Stop including size prefix in the compressed stream.

Since the C decompressor doesn't support this, it is a bit counter-productive.

Also added a metric ... amount of trace print() calls in the Python code, for debugging.

I think it works now, at least for suitably small values of "works". Nice!