README: Fix more links

Change link to Gitter and fix links to Travis

Semaphore still points to diydrones (I believe that has to be changed by the team in Semaphore control panel first: https://semaphoreci.com/docs/organizations/renaming-an-organization.html)

README.md

@@ -1,10 +1,10 @@
 #ArduPilot Project#
 
-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/diydrones/ardupilot?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/ArduPilot/ardupilot?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 [![Build SemaphoreCI](https://semaphoreci.com/api/v1/projects/4d28a40d-b6a6-4bfb-9780-95d92aabb178/667563/badge.svg)](https://semaphoreci.com/diydrones/ardupilot)
 
-[![Build Travis](https://travis-ci.org/diydrones/ardupilot.svg?branch=master)](https://travis-ci.org/diydrones/ardupilot)
+[![Build Travis](https://travis-ci.org/ArduPilot/ardupilot.svg?branch=master)](https://travis-ci.org/ArduPilot/ardupilot)
 
 ### The ArduPilot project is made up of: ###
 >>ArduCopter (or APM:Copter) : [code](https://github.com/ArduPilot/ardupilot/tree/master/ArduCopter), [wiki](http://copter.ardupilot.com)