Create the ability to process multiple files

With Python and `libproton`, the startup time of a proton process is significant. It takes too long to be practical to process a full competition's worth of matches with one process per match. As a result, `srcomp` is currently coupled to the internal API of libproton rather than invoking a proton process.

Being able to process multiple files in one run of the program means that all files can be processed while suffering the startup time only once.
should be 2.0.0?