upgrade to jsdoc-toolkit 3

- upgrade to jsdoc toolkit 3
- most of the behaviour is now configurable. the jsdoc command is just a thin wrapper around the jsdoc-toolkit command with a number of defaults. the defaults, the jsdoc-toolkit version and the template can all be changed by the user.
- i've held of doing too much styling on the new template until we decide what we want the new template to look like