[python] Make Context a namedtuple
[python] Make Context a namedtuple

chenwenbin928/tchannel,vanloswang/tchannel,Zirpon/tchannel,bunnyblue/tchannel,benfleis/tchannel,RyanTech/tchannel,hustxiaoc/tchannel,vanloswang/tchannel,i/tchannel,RyanTech/tchannel,Zirpon/tchannel,Zirpon/tchannel,hustxiaoc/tchannel,vanloswang/tchannel,savaki/tchannel,i/tchannel,sasa233/tchannel,savaki/tchannel,i/tchannel,chenwenbin928/tchannel,RyanTech/tchannel,hustxiaoc/tchannel,sasa233/tchannel,chenwenbin928/tchannel,bunnyblue/tchannel,savaki/tchannel,benfleis/tchannel,bunnyblue/tchannel,benfleis/tchannel,sasa233/tchannel