Add ability to print bounded progressbar

Passing in a `count` will now result in a bounded progressbar that
indicates to the user how close the job is to completion
Make seq underlying bounded progress seq infinite

Less likely to hit nasty wrong length bugs, though I'm pretty sure the
previous implementation worked fine too.
Make installation instructions clearer
Fix test file
Factor progress seq functions into their own namespace
Automatically choose a progress seq based on the input seq

If the input seq implements clojure.lang.Counted, use a bounded seq.
If not, use an unbounded seq.

We'll want to extend this to other java types eventually, but this
gives the right framework.
Update documentation for auto-progress seq selection
Fix protocol issue

There's no prefer system for protocols, so switch base implementation
to Object rather than another interface. Things get freaky with
protocols and interfaces...