* Updates for python36 and scl
Latest changes to installing the scl environment don't include the scl command, scl-utils is needed along w/ the proper repository in Centos7 to be enabled via RH and then downloaded to the environment which you are building and then SCL commands will work and setting python environment for bash will work too.
* Minor changes
I attempted to follow the documentation to install HASS on to Centos 7.5 minimal. I found gcc gcc-c++ were required for hass to complete the auto install of various python packages and systemd-devel for zwave. Figure this information/step should be included in the installation wiki for centos.
* Updated SCL command to Python 3.6 instead of 3.5
Instructions are for installing Python 3.6 but the scl command given assumes you have Python 3.5
* Updated autostart systemd template to use Python 3.6
