Links in the python getting started need updating

[fatmaf]

Hi, the links in the python getting started bit (https://github.com/doganulus/reelay/blob/master/docs/gs_python.md) need updating.

• The source code of this tutorial can be found here -> https://github.com/doganulus/reelay/tree/master/apps/tutorial/door_open_warning/python
• If you haven't already, please check the documentation on discrete and dense time behaviors before proceeding. -> https://github.com/doganulus/reelay/blob/master/docs/behaviors.md