Updated readme...there have been a lot of issues with pronterface on Lion. The...

Updated readme...there have been a lot of issues with pronterface on Lion. The link I added should clarify some of the confusion.

README.md

@@ -25,6 +25,7 @@ Download the following, and install in this order:
   1. Ensure that the active Python is the system version. (`brew uninstall python` or other appropriate incantations)
   2. Download an install [wxPython2.8-osx-unicode] matching to your python version (most likely 2.7 on Lion, 
         check with: python --version) from: http://wxpython.org/download.php#stable
+  Known to work PythonWX: http://superb-sea2.dl.sourceforge.net/project/wxpython/wxPython/2.8.12.1/wxPython2.8-osx-unicode-2.8.12.1-universal-py2.7.dmg
   3. Download and unpack pyserial from http://pypi.python.org/packages/source/p/pyserial/pyserial-2.5.tar.gz
   4. In a terminal, change to the folder you unzipped to, then type in: `sudo python setup.py install`