Added CC notice to readme.

README.textile

@@ -1,3 +1,7 @@
 h1. SOLID Ruby
 
 This is a presentation discussing Bob Martin's SOLID design principles with respect to dynamic languages (in particular, Ruby).
+
+
+h2. Licence
+<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/us/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-sa/3.0/us/88x31.png" /></a><br /><span xmlns:dc="http://purl.org/dc/elements/1.1/" property="dc:title">SOLID Ruby</span> by <a xmlns:cc="http://creativecommons.org/ns#" href="http://github.com/jimweirich/presentation_solid_ruby" property="cc:attributionName" rel="cc:attributionURL">Jim Weirich</a> is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/us/">Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License</a>.<br />Based on a work at <a xmlns:dc="http://purl.org/dc/elements/1.1/" href="http://github.com/jimweirich/presentation_solid_ruby" rel="dc:source">github.com</a>.