Feature - use git branch in logic for docker image naming

Include in image name when building artifacts
If branch = master, mark in docker as latest, else, mark with branch
name.
Remove old debugging, and some new stuff
jenkins outputs $GIT_BRANCH as (repo)/(branch), so get just branch
Use bourne-shell string matching

Previous attempt was bash-specific
if/fi spacing important. add debugging logs
String matching, yo
Syntax, spelling, debugging
Wrong variable name
Docker push and docker tag are both important
fix formatting
Merge pull request #4 from anchor/git_branch

Use git topic branches as docker tag/image name if not master