How to stream audio and video in Linux Mint 18 Sarah from your computer to Google chromecast on your TV.

Install the following dependencies running in terminal:
$ sudo apt-get install python2.7 python-pip python-flask python-psutil python-setuptools python-mutagen python-gi vorbis-tools sox lame flac faac opus-tools libuv1 nodejs youtube-dl

Also, download and install:
1) $ sudo dpkg -i libprotobuf10_3.0.0-7ubuntu3_amd64.deb
2) $ sudo dpkg -i python-protobuf_3.0.0-7ubuntu3_amd64.deb
3) $ sudo dpkg -i python-pychromecast_0.7.7-2_all.deb
from https://ubuntu.pkgs.org and:
4) $ sudo dpkg -i mkchromecast_0.3.7-1_all.deb
from http://mkchromecast.com/

If there are any problems with the dependencies run $ sudo apt-get -f install to fix them

Install $ sudo apt-get install python-pyqt5 to get the tray applet and a GUI.

That's all  ;-)