Fixes to readme
Fixes to readme

Fixes #1830, and updates GCP branding.
piosz/heapster,krzyzacy/heapster,bluebreezecf/heapster,Stackdriver/heapster,Stackdriver/heapster,piosz/heapster,bluebreezecf/heapster,whuwxl/heapster,whuwxl/heapster,krzyzacy/heapster