updated dependencies based on jasper's experience

README

@@ -1,7 +1,8 @@
 DEPENDENCIES:
 theano: http://deeplearning.net/software/theano/
 numpy
-matplotlib: http://matplotlib.sourceforge.net/
+scipy
+(optional) matplotlib: http://matplotlib.sourceforge.net/
 
 Note: maccam912 reports that the link above is currently down (Feb 28, 2012) but says, "I see you can still get it with 'easy_install Theano' or downloading it from http://pypi.python.org/pypi/Theano or the repo on github. Just a heads up. I don't use git or github often so I wasn't sure if the issues section was the place to point this out or not."