Fix broken YAML parsing on later Rubies with Psych >=4.0

YAML.load is now interpreted as YAML.safe_load, which breaks where the
YAML file contains aliases. If we can assume our yaml files are
trusted (since this a development tool), we can check for the presence
of YAML.unsafe_load and use it instead if it exists.

auto/yaml_helper.rb

@@ -0,0 +1,19 @@
+# ==========================================
+#   Unity Project - A Test Framework for C
+#   Copyright (c) 2007 Mike Karlesky, Mark VanderVoord, Greg Williams
+#   [Released under MIT License. Please refer to license.txt for details]
+# ==========================================
+
+require 'yaml'
+
+module YamlHelper
+  def self.load(body)
+    YAML.respond_to?(:unsafe_load) ?
+      YAML.unsafe_load(body) : YAML.load(body)
+  end
+
+  def self.load_file(file)
+    body = File.read(file)
+    self.load(body)
+  end
+end