Add tests

[monkeyman192]

It would be good to get some tests up and working properly.
There are a number of tests we should implement:

• Proc-gen mode - Ensure descriptor is generated with the data.
• Normal file - No proc-gen or batch mode. Model with at least one locator, reference, collision and mesh node in some kind of hierarchy. With materials provided within the blend file. Can test to ensure materials are placed in the right location etc.
• UV winding order - Mirrored faces should not have flipped binormals.
• Animation file - Pending animations being fixed - Simple animation with a single animation on the object - Name of animation file should be the same as the name of the scene file etc (and data in entity should reflect this by having no path)
• Animation file 2 - Pending animations being fixed - File with multiple animations. The files should be placed inside an anim sub folder and the paths in the entity should reflect their locations correctly.
• File with custom entity properties and action triggers.

These tests can also be used as example for how to use the different features of NMSDK.

The tests will be written using pytest to call them. They will also use the batch script that calls NMSDK from command line to automate the process