Automated regression test infrastructure for CakeML.

apiLib.sml: The API that the server and worker agree on.

flock.sml: Maintenance tool: acquire the lock that is used by the server to run a command without interfering with the server.

server.sml: Implements the server-side regression-test API as a CGI program.

serverLib.sml: Functions for manipulating the queues in the filesystem on the server, including for getting information from GitHub with which to update them.

utilLib.sml: Small library of useful code.

worker.sml: Worker that claims and runs regression test jobs.