Python release (#3966)

* Remove 3.4

* Add note

source/_docs/installation/python.markdown

@@ -22,7 +22,7 @@ Running these commands will:
  - Install Home Assistant
  - Launch Home Assistant and serve the web interface on [http://localhost:8123](http://localhost:8123)
 
-If you're running a Linux-based platform, we suggest you follow the [VirtualEnv instructions](/docs/installation/virtualenv/) to avoid using `root`.
+If you're running a Linux-based platform, we suggest you follow the instructions for a [virtual environment](/docs/installation/virtualenv/) to avoid using `root`.
 
 Video tutorials of this process for various operating systems are available here:
 
@@ -30,3 +30,4 @@ Video tutorials of this process for various operating systems are available here
  - [macOS](https://www.youtube.com/watch?v=hej6ipN86ls)
  - [Ubuntu 14.04](https://www.youtube.com/watch?v=SXaAG1lGNH0)
 
+Keep in mind that the used operating systems and the shown software releases may be outdated.

source/_docs/installation/troubleshooting.markdown

@@ -14,7 +14,7 @@ It can happen that you run into trouble while installing Home Assistant. This pa
 
 
 #### {% linkable_title pip3: command not found %}
-This utility should have been installed as part of the Python 3.4 installation. Check if Python 3.4 is installed by running `python3 --version`. If it is not installed, [download it here](https://www.python.org/getit/).
+This utility should have been installed as part of the Python installation. Check if Python is installed by running `python3 --version`. If it is not installed, [download it here](https://www.python.org/getit/).
 
 If you are able to successfully run `python3 --version` but not `pip3`, install Home Assistant by running the following command instead: