Make random cowsay truly random

Also adds a cowsay whitelist config option, because there are some
truly NSFW stencils that come with cowsay by default.

examples/ansible.cfg

@@ -143,6 +143,20 @@ ansible_managed = Ansible managed: {file} on {host}
 # set to 1 if you don't want cowsay support or export ANSIBLE_NOCOWS=1 
 #nocows = 1
 
+# set which cowsay stencil you'd like to use by default. When set to 'random',
+# a random stencil will be selected for each task. The selection will be filtered
+# against the `cow_whitelist` option below.
+#cow_selection = default
+#cow_selection = random
+
+# when using the 'random' option for cowsay, stencils will be restricted to this list.
+# it should be formatted as a comma-separated list with no spaces between names.
+# NOTE: line continuations here are for formatting purposes only, as the INI parser
+#       in python does not support them.
+#cow_whitelist=bud-frogs,bunny,cheese,daemon,default,dragon,elephant-in-snake,elephant,eyes,\
+#              hellokitty,kitty,luke-koala,meow,milk,moofasa,moose,ren,sheep,small,stegosaurus,\
+#              stimpy,supermilker,three-eyes,turkey,turtle,tux,udder,vader-koala,vader,www
+
 # don't like colors either?
 # set to 1 if you don't want colors, or export ANSIBLE_NOCOLOR=1
 #nocolor = 1