How to zoom out, without mouse/scrollwheel?

[JanOschii]

Maybe a good info for the readme too.

[jmm]

One way I've found to zoom all the way out, at least in Chrome Mac, is to press Esc. But it'd be really nice to be able to incrementally zoom in / out using the keyboard, and it'd be nice if you could drag a box with the mouse to zoom in. A way to filter by typing path regexes would also be nice.