Add if python is present in system (#218)
Add if python is present in system (#218)

* Use python2 to build a python2 extension.

Reasoning: some environments use python3 by default

* Add checks for various environments

Env1: Python2 isn't installed
Env2: Python3 isn't installed
Env3: no python is installed

Yggdroot/LeaderF,Yggdroot/LeaderF,Yggdroot/LeaderF