Merge pull request #8 from rptb1/add-template-context

Adding a template_context keyword to allow passing of fields to templates
add "Licensing and Author" section in the doc
use None as a default value of template_context
update docs
Allow hidden files (starting with '.') to be shown in indexes.
Add the keyword parameter "show_hidden" to both AutoIndex init and render_autoindex methods, with the former providing a default for the latter.  The logic was already there in the "explore" but had not been plumbed through to the external interface.