Display tag if we are in a tag and master when new repo

Ok, now tag will be display if we are in a tag. If in a new repo, master will be displayed and otherwise the current branch.

This is done by running the following commands (one after other in case of failure):

• git symbolic-ref --short HEAD
• git describe --exact-match HEAD
• git rev-parse --short HEAD

Further improvements

• Switch Icon if we are in a tag

#24 (closed)