Merge branch 'gh-pages' into feature-1-se-seminar
add slide and images for Labels; #1
add / update content: branching; #1
update branching / commit messages; #1
commit messages: linking of issues, usernames and commit hashes; #1
add motivation for issue number in branch name; #1
add and clean-up content for intro slides; #1
add lessons learned and summary to outro slides; #1
add / update content for issues slide; #1
add / update content for easy-deploys slide; #1
add content to pull-requests slide; #1
update git-aliases content; #1
Merge branch 'feature-1-se-seminar' into gh-pages