Enhancement request: progress meter

[Firehed]

The default interaction (on 2.0.0) when running the checker has no indication that it's working when the analysis is running. The first couple of times I ran this, I ended up C-c'ing the process thinking it was stuck or otherwise waiting for input before realizing that it's just doing a bunch of stuff in the background and I need to wait. This made for a poor and confusing first experience with the tool.

At a minimum, it would be great to print a message indicating that the analysis has started and results will be printed when available. Ideally, some sort of progress meter (like what PHPUnit does) would make it exceedingly clear that analysis is running.