Remove old code that has deprecation warnings:

• Flask.ext
• Flask.init_jinja_globals
• Flask.error_handlers
• Flask.request_globals_class
• Flask.static_path
• send_file mimetype guessing removed in 0.12Remove deprecation warnings for add_etags & mimetype guessing for send_file() #1849
• Request.module
• scripts/flask-07-upgrade.py