Typo fixes in doc

doc/install.txt

@@ -234,8 +234,8 @@ From here, the easiest way to get started is (this requires setuptools_ or distr
 
 .. note::
 
-   "python setup.py develop ..." don't work on Python 3 as it don't call
-   the converter from Python2 code to Python 3 code.
+   "python setup.py develop ..." does not work on Python 3 as it does not call
+   the converter from Python 2 code to Python 3 code.
 
 This will install a ``.pth`` file in your ``site-packages`` directory that
 tells Python where to look for your Theano installation (i.e. in the

theano/configdefaults.py

@@ -417,8 +417,8 @@ AddConfigVar('compute_test_value_opt',
              in_c_key=False)
 
 AddConfigVar('unpickle_function',
-             ("Replace unpickled Theano function with None",
-              "This is useful to unpickle old graph that pickled"
+             ("Replace unpickled Theano functions with None. "
+              "This is useful to unpickle old graphs that pickled"
               " them when it shouldn't"),
              BoolParam(True),
              in_c_key=False)