Update Free Software Foundation addresses

Update all references to the FSF physical address
to use the web address: http://www.gnu.org/licenses
docs: Ignore meta-class bases in dynamic docstring generation

Skip attempts at generating a doc string for GObject meta-class bases
since they do not contain an __info__ attribute.
This circumvents errors with documentation generators (Sphinx).
Quote argument names in initializer deprecation warning

Add quotation marks around names of deprecated positional arguments.
This makes the message clearer in stating what has been deprecated
in cases when only a single argument is displayed.
docs: Standardize Python doc strings

Use consistent doc string quotations (three double quotes).
Update usage of GObject.GObject in docs to GObject.Object.
Use reStructuredText markup for parameter annotations, instance variables,
admonitions, and code examples.
This allows for better Sphinx documentation generation for the project.
Preliminary style guide:
https://wiki.gnome.org/Projects/PyGObject/StyleGuide