Adding upstream version 0.13.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

docs/demos/scenario.txt

@@ -0,0 +1,75 @@
+sudo pip uninstall gitlint
+
+virtualenv ~/gitlint-demo
+
+source ~/gitlint-demo
+
+mkdir ~/my-git-repo
+
+git init
+
+echo "test" > myfile.txt
+
+git add .
+
+git commit
+
+WIP: This is a commit message title.
+Second line not empty
+This body line exceeds the defacto standard length of 80 characters per line in a commit m
+essage.
+
+cd ..
+
+
+asciicinema rec demo.json
+
+------------------------------------
+
+pip install gitlint
+
+# Go to your git repo
+
+cd my-git-repo
+
+# Run gitlint to check for violations in the last commit message
+
+gitlint
+
+# For reference, here you can see that last commit message
+
+git log -1
+
+# You can also install gitlint as a git commit-msg hook
+
+gitlint install-hook
+
+# Let's try it out
+
+echo "This is a test" > foo.txt
+
+git add .
+
+git commit
+
+WIP: Still working on this awesome patchset that will change the world forever!
+
+[Keep commit -> yes]
+
+# You can modify gitlint's behavior by adding a .gitlint file
+
+gitlint generate-config
+
+vim .gitlint
+
+gitlint
+
+# Or specify additional config via the commandline
+
+gitlint --ignore title-trailing-punctuation
+
+# For more info, visit: http://jorisroovers.github.io/gitlint
+
+exit
+
+------------------------------