Show spinner while queries are executing

Fixes #235 

Here's what it looks like (I artificially added 2s of latency to make it more obvious):
![cql spinner](https://cloud.githubusercontent.com/assets/98301/5306116/a762c3ba-7bcf-11e4-995a-a0d93617af5c.gif)

(I also took the opportunity to delete some unused code.)
Does this obsolete (clear?) pending requests?