add spdy/3.1 to indicator.js

but it's need icon-spdy3.1.png but I don't know how to create it :(
add icon for spdy/3.1
set npnNegotiatedProtocol as default info to show spdy/3.1
Merge pull request #14 from matsuu/spdy-3.1

Spdy 3.1 support
Release 0.5.0
Changelog