Fix Bootstrap terminology & website link

See http://getbootstrap.com/about/#brand

NOTICE

@@ -5,7 +5,7 @@ Select2
 
 Distributed under `APLv2 <http://www.apache.org/licenses/LICENSE-2.0>`_.
 
-Twitter Bootstrap
+Bootstrap
 =================
 
 Distributed under `APLv2 <http://www.apache.org/licenses/LICENSE-2.0>`_.

README.rst

@@ -97,6 +97,6 @@ Please note that you will need to install some additional dependencies in order
 3rd Party Stuff
 ---------------
 
-Flask-Admin is built with the help of `Twitter Bootstrap <http://twitter.github.com/bootstrap/>`_ and `Select2 <https://github.com/ivaynberg/select2>`_.
+Flask-Admin is built with the help of `Bootstrap <http://getbootstrap.com/>`_ and `Select2 <https://github.com/ivaynberg/select2>`_.
 
 If you want to localize your application, install the `Flask-BabelEx <https://pypi.python.org/pypi/Flask-BabelEx>`_ package.