params: add multi-level verbosity

Now we can have --verbose=[012], so that the default (0) is still quiet,
the easy verbose flag (--verbose or -v) is noisy but useful (1), and if
you really want some extra noise, you can choose (2). Right now, there
is some minimal extra noise in (2), but this may be expanded if we want
more run-time debuggability, rather than recompiling with 'make debug'.