Handle more ResourceWarning issues. admin.py - remove unneeded close. mailer.py - close debug log file. indexer.py - close read of version file memorydb.py - close python files being compled. Similiar to instance. not sure why it's compoing things and not just letting instance do it. .travis.ymv disable all except 3.9-dev till we get a handle on errors. also increase errors to 50 from 20.

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)