Enabling dispatch to work from subfolders, by introducing a new ini setting - site.url.

This commit also adds two helper functions: site_url() which returns home URL for dispatch,
and site_path(), which returns the relative path from the domain root (both of these are
handy in templates).
Merge pull request #4 from martinaglv/master

Enabling dispatch to work from subfolders
fixes #8, optional params to dispatch() for cli testing