installation and handling the schema file in examples

[chrishavlin]

In reviewing #36 I got to wondering about some installation details. Specifically, how should a user specify the schema file when writing a json?

Once we're up on pypi, a user will be able to install with pip install analysis_schema. This will copy down yt_analysis_schema.json but how would a user specify that file in a json? they'd have to know where pip put the package, which will depend on their environment...

So in all the examples, should we be specifying the schema location as a url? Right now we'd have to point to the raw github file, which would be long and ugly:

{
    "$schema": "https://raw.githubusercontent.com/data-exp-lab/analysis_schema/master/analysis_schema/yt_analysis_schema.json",
 ....
}

once we have full docs, we could host a schema file there.

[chrishavlin]

potentially good option: add a config command to the click cli, recommend users run it after install. it could copy the schema file to a user-supplied directory so that they know where it lives locally.