add example lua stuff

contrib/lua/memeposting.lua

@@ -0,0 +1,16 @@
+
+-- simple replacements demo
+
+function span_text(str, class)
+  return string.format("<span class='%s'>%s</span>", class, str)
+end
+
+function wobble_text(str)
+  return span_text("wobble", str)
+end
+
+-- generate extra markup
+function memeposting(prefix, body)
+  body = string.gsub(body, "<(%w+)>", wobble_text)
+  return body
+end