Add date examples to cookbook. Closes #113.

docs/cookbook/filtering.rst

@@ -41,6 +41,23 @@ This snippet filters the dataset to incomes between 100,000 and 200,000.
 
     new_table = table.where(lambda row: 100000 < row['income'] < 200000)
 
+Filter to date range
+====================
+
+This snippet filters the dataset to events during the summer of 2015:
+
+.. code-block:: python
+
+    import datetime
+
+    new_table = table.where(lambda row: datetime.datetime(2015, 6, 1) <= row['date'] <= datetime.datetime(2015, 8, 31))
+
+If you want to filter to events during the summer of any year:
+
+.. code-block:: python
+
+    new_table = table.where(lambda row: 6 <= row['date'].month <= 8)
+
 Filter to top x%
 ================
 

docs/cookbook/sorting.rst

@@ -11,6 +11,14 @@ Order a table by the :code:`last_name` column:
 
     new_table = table.order_by('last_name')
 
+Sort by date
+============
+
+Sorting by dates also wrks as expected:
+
+.. code-block:: python
+
+    new_table = table.order_by('birthdate')
 
 Multicolumn sort
 ================
@@ -31,4 +39,3 @@ Randomizing order
     import random
 
     new_table = table.order_by(lambda row: random.random())
-