Some more typos (#219)

I went with the American spelling of "fulfill" instead of the British
"fulfil".

docs/examples.rst

@@ -263,7 +263,7 @@ And sometimes you even want mutable objects as default values (ever used acciden
 More information on why class methods for constructing objects are awesome can be found in this insightful `blog post <http://as.ynchrono.us/2014/12/asynchronous-object-initialization.html>`_.
 
 Default factories can also be set using a decorator.
-The method receives the partially initialiazed instance which enables you to base a default value on other attributes:
+The method receives the partially initialized instance which enables you to base a default value on other attributes:
 
 .. doctest::
 

docs/how-does-it-work.rst

@@ -51,7 +51,7 @@ Immutability
 
 In order to give you immutability, ``attrs`` will attach a ``__setattr__`` method to your class that raises a :exc:`attr.exceptions.FrozenInstanceError` whenever anyone tries to set an attribute.
 
-In order to circumvent that ourselves in ``__init__``, ``attrs`` uses (an agressively cached) :meth:`object.__setattr__` to set your attributes.  This is (still) slower than a plain assignment:
+In order to circumvent that ourselves in ``__init__``, ``attrs`` uses (an aggressively cached) :meth:`object.__setattr__` to set your attributes.  This is (still) slower than a plain assignment:
 
 .. code-block:: none
 

docs/overview.rst

@@ -2,7 +2,7 @@
 Overview
 ========
 
-In order to fullfil its ambitious goal of bringing back the joy to writing classes, it gives you a class decorator and a way to declaratively define the attributes on that class:
+In order to fulfill its ambitious goal of bringing back the joy to writing classes, it gives you a class decorator and a way to declaratively define the attributes on that class:
 
 .. include:: ../README.rst
    :start-after: -code-begin-

tests/test_dark_magic.py

@@ -183,7 +183,7 @@ def test_subclassing_with_extra_attrs(self, cls):
     def test_subclass_without_extra_attrs(self, base):
         """
         Sub-classing (where the subclass does not have extra attrs) still
-        behaves the same as a subclss with extra attrs.
+        behaves the same as a subclass with extra attrs.
         """
         class Sub2(base):
             pass