Summary: Constrain format of classname and document Define the format of a valid classname. Updated design doc, function doc and glossary to document format. Error message for case where we have a redefinition of a classname now says why ValueError is raised since we are raising ValueError for incorrect classname format as well. Tests for all cases including verification of cause for ValueError exceptions.

def audit_html_files(db, cl, nodeid, newvalues):
    if 'type' in newvalues and newvalues['type'] == 'text/html':
        newvalues['type'] = 'text/plain'
    

def init(db):
    db.file.audit('set', audit_html_files)
    db.file.audit('create', audit_html_files)