Set release date, fix formatting.

CHANGES.md

@@ -1,15 +1,15 @@
 # Release notes
 
-## 0.2.1 (unreleased)
+## 0.2.1 (2014-12-20)
 
-- changed type checking keyword argument names: 'opt' -> 'or_none'
-  and 'nodups' -> 'unique'
+- changed type checking keyword argument names: `opt` -> `or_none`
+  and `nodups` -> `unique`
 - improved error messages for constructing Structs
 - significant updates to readme and examples
-- using opt=True on TypedField no longer implies that None is
+- using `opt=True` on `TypedField` no longer implies that `None` is
   the default value
-- made mixin version of checktype() and checktype_seq()
-- added check() and normalize() hooks to TypedField
+- made mixin version of `checktype()` and `checktype_seq()`
+- added `check()` and `normalize()` hooks to `TypedField`
 - accessing fields descriptors from classes is now permissible
 - added support for default values in general, and optional values
   for type-checked fields