Add Rake task to run all working samples

Usage: rake samples

This task reads the list of working samples from samples/README,
shuffles the list, and executes each sample. When you quit the current
sample, the next one spins up. You wouldn't want to run this all the
time (it takes 7 or 8 minutes on my machine at the moment), but it's
a nice sanity check.

Rakefile

@@ -125,6 +125,16 @@ namespace :spec do
 
 end
 
+desc "Run all working samples"
+task :samples do
+  samples_dir = "samples"
+  samples = File.read("#{samples_dir}/README").lines
+  samples.map {|s| s.sub(/#.*$/, '')}.map(&:strip).select {|s| s != ''}.shuffle.each do |sample|
+    puts "Running #{samples_dir}/#{sample}...quit to run next sample"
+    system "bin/shoes #{samples_dir}/#{sample}"
+  end
+end
+
 begin
   require 'yard'
 

samples/README

@@ -1,8 +1,11 @@
-Here's a list of the samples in this directory that work. Please
-add to this list as you implement features!
+# Here's a list of the samples in this directory that work. Please
+# add to this list as you implement features!
+#
+# NOTE: Comment out anything that isn't a filename, so we can execute this list.
+#       See the `rake samples` task
 
 simple-animate.rb
-simple-move.rb (works but looks a bit weird on Linux, see issue #59)
+simple-move.rb # (works but looks a bit weird on Linux, see issue #59)
 simple-bounce.rb
 simple-oval.rb
 simple-sound.rb