No option to get version information in (dev version on current master)

[tovrstra]

I just tested Tectonic to see how deep the water is. :) Nice project!

I noticed just one odd thing (with development version d7f3275). There seems to be no way to get version information from the CLI. None of these work:

./target/debug/tectonic --version
./target/debug/tectonic -X --version
./target/debug/tectonic -X show version

I'm not sure which one is the proper way, if any?