Update install kite

Refers to 0.18.0. Changed it so that 0.18.0 is an example, rather than the only form of the command.
We actually want this to be the current Kite version, so it should be a field in the `_config.yml` file instead. I have it in my working copy and was going to submit it once the major changes there are in. This should be fine for now, but there is no need to consider it an example.