Shorten class names

[ryanhiebert]

Some classes, like ToolProvider and ToolConsumer, seem a bit long-winded. It may be preferable to change those to Provider and Consumer, and perhaps other classes similarly.

Because this is a breaking change, we'll want to make it as soon as is reasonable, and before we release 1.0.

[ryanhiebert]

While I'd like to see the class names change, I think that this should be done with as much open input as possible, so I don't want to hold up an initial release to PyPI for this work.