Prepare for v2.6.7

CHANGELOG.rdoc

+== 2.6.7
+* Nothing annotated unless options[:model_dir] is specified, #234
+
 == 2.6.6
 * Makes it possible to wrap annotations, #225
 * Fix single model generation, #214

lib/annotate/version.rb

 module Annotate
   def self.version
-    '2.6.6'
+    '2.6.7'
   end
 end