Fix CherryPy installation process on OSX.
Fix CherryPy installation process on OSX.

Do not blatantly install CherryPy using sudo. Detect if we are in
virtualenv first. Then try to check if Python is installed by homebrew.
Both instances do not require sudo. Finally, prompt the user if they
want to install CherryPy.

rudeb0t/simple-rtmp-server,rudeb0t/simple-rtmp-server,rudeb0t/simple-rtmp-server,rudeb0t/simple-rtmp-server,rudeb0t/simple-rtmp-server,rudeb0t/simple-rtmp-server