Moved description of _urlopener adjacent to the related functions. Added missing import to example code.
Moved description of _urlopener adjacent to the related functions.
Added missing import to example code.

Added documentation for pathname2url(), url2pathname().
Closes SF bug #623196.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator