2.0.0

• Feature : All of page handlers have parameter Event instead of a dict.
• Feature : Support a thread setting
• Deprecated : remove callback_postback, callback_quick_reply
• Feature : Add a decorator - page.callback(['payload'], types=['QUICK_REPLY', 'POSTBACK'])
• Feature : Add a page method, get_user_profile(fb_user_id), to get facebook user profile