* use maven to package docs

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>

* include version information in documentation builds

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>

* Use htmldoc assembly if available, fallback to manual zip

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>