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
Heh, interesting. I hadn't realized this happens synchronously regardless of whether a callback is passed. That's probably the cause of the freeze up when adding big folders to the workspace. I'll have to look into fixing that down the road.