Add possibility to check blender installation

README.md

@@ -66,6 +66,18 @@ python setup.py install
 ```
 
 ## Blender-python version
+Navipy can be interfaced with blender. It is highly recommended to use the same version of packages of blender when doing so, in order to reduce problem of compatibility.
+To determine the packages that you will need, you can run the script: `navipy/script/check_blender_versions_pip.py` in blender or via commandline:
+
+```
+blender -b -P check_blender_versions_pip.py
+```
+
+It will create a textfile containing all packages used by blender. They can be installed in your virtualenvironment (prior to navipy) by doing:
+```
+pip install -r requirement.txt
+```
+
 | Blender version | Python version |
 | --------------- | -------------- |
 | 2.79b           | 3.5.3          |

navipy/scripts/check_blender_versions_pip.py

+"""
+List all installed packages in a python installation
+by using pip.
+
+It can be used to install a virtual environment, so that it matches
+another installation (for example blender)
+"""
+import pip
+
+
+installed_packages = pip.get_installed_distributions()
+installed_packages = sorted(["%s==%s" % (i.key, i.version)
+                             for i in installed_packages])
+with open('requirement.txt', 'w') as cfile:
+    for line in installed_packages:
+        print(line)
+        cfile.write(line+'\n')