Make recording offset testing easier.

[Chris Earley]

Right now the only way to figure out if your stream delay offsets are working is to let the system run for a few days and check the resulting recordings. This process can take the better part of a week and yields a collection of oddly truncated videos that can be a mess to clean up.

I propose a --test-record command line argument that pulls the NHK World schedule and adds a one-time recording job for the next upcoming program to the scheduler. It should then provide the user with the filename of the show to be recorded so they can view it later and check their offset settings without having to wait for the next formal scrape of the NHK World schedule.

This feature should ignore any whitelist/blacklist settings.