7061: Wrap User...._progress in a context manager

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@23091 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
7061: Wrap User...._progress in a context manager

ensure end_progress is called when exception is raised

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@23092 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
7061: User.progress

docstrings

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@23093 4ae1f11a-8b86-4847-b8af-ab372f36d1fd