Added *= and /= operators and friend function sqrt()
Make compliant to coding conventions (remove tabs)
Merge branch '1247-add-operators-and-friends-to-GSkymap' into integration
Merge branch '1247-add-operators-and-friends-to-GSkymap' into integration (reverted from commit d809ce80f9e426a6b580362b789c1e15f6b27fff)