Add a file for G+ webmaster verification

https://www.google.com/webmasters/verification/verification?hl=en&siteUrl=http://davesteele.github.io/&authuser=0&theme=wmt&continue=https://www.google.com/webmasters/tools/dashboard?hl%3Den%26siteUrl%3Dhttp://davesteele.github.io/%26authuser%3D0%26sig%3DALjLGbNrYdSveKxB7XJaYhzbbESbPvoIDQ&pluuu