Changes Travis badge to point at official repo.
Changes Travis badge to point at official repo.

It wasn't working for my repo, anyway, since I didn't have any Travis
config in default, only on this branch.

Charcoal-SE/ChatExchange,Charcoal-SE/ChatExchange,hichris1234/ChatExchange,hichris1234/ChatExchange,ByteCommander/ChatExchange6,ByteCommander/ChatExchange6