Working on series of simple examples.

Clean up sqladapter for now. Make saving to file path of builders more
consistent. Add EXTENSION class value to builder, for their typical
file extension. Add getRootPath to component. Make helloWorld example
work, saving to html file. Remove getStylePath from page. Components
should not know paths. Make COPYTO_config.py work if config.py is
absent (as in original git download). Cleanup doingbydesign example.
Preparations for KirbyBlog example.