Can't install 'Screencast keys' add-on User preferences, add-ons, won't recognize .py (screencast keys) file when I try to "install from file".  Oddly, it won't show up in Blender when the .py script is put into program files alongside all the all "view" files ending in .py.
There is a mod of the addon that works:

cd ~/.blender/*/scripts/addons/

git clone https://github.com/chromoly/blender-ScreencastKeysMod.git

then activate the addon

3D View > Properties Panel >Screencast Keys