Usage:
use `tprofile.ProfileMeta' as the metaclass of handler subclass or base handler class.

Example:
import tornado.web
from tprofile import ProfileMeta

def condition(self):
...return True if self.get_argument('profile', None) == "1" else False
ProfileMeta.set_condition(condition)

class BaseHandler(tornado.web.RequestHandler):
...__metaclass__ = ProfileMeta

class MainHandler(BaseHandler):
...def get(self):
......pass

