Prepare 3.0.0 [skip ci]

Author: thekid

ChangeLog.md

@@ -3,7 +3,7 @@ Data sequences change log
 
 ## ?.?.? / ????-??-??
 
-## 2.3.0 / 2015-06-01
+## 3.0.0 / 2015-06-01
 
 * Renamed whenNull() to `isAbsent()` in util.data.Optional. This is
   more consistent with the present() method. See pull request #23