Reduce number of compile-time warnings

Hi,

I decided to try to fix issue #1658 . Here's my first attempt. 

- fixed most of the `Wrong number of args` warnings
- fixed couple of `Use of undeclared Var` in object.cljs, app.cljs and command.cljs
That seems reasonable. What kind of things are we interested in deprecating in general – just functions? Behaviours/commands?

Setting up warnings for those should be reasonably easy but I don't know of any way to do that for CSS selectors, which I think have also changed quite a bit.