Remove the Travis build for Python 2.6
Remove the Travis build for Python 2.6

This is no longer supported by the irc library cobe uses.

tiagochiavericosta/cobe,pteichman/cobe,pteichman/cobe,tiagochiavericosta/cobe,meska/cobe,DarkMio/cobe,meska/cobe,DarkMio/cobe,LeMagnesium/cobe,LeMagnesium/cobe