Added scalp mesh to hair engine

[Upliner]

No description provided.

[animate1978]

So this is able to be merged... however the Package builder for Python 3.6 to 3.9 are failing.

./__init__.py:2489:16: F722 syntax error in forward annotation 'Add Curve Guide'
        name = "Add Curve Guide",
               ^
./__init__.py:2490:23: F722 syntax error in forward annotation 'Add curve guide to hair'
        description = "Add curve guide to hair",
                      ^
2     F722 syntax error in forward annotation 'Add Curve Guide'
2
Error: Process completed with exit code 1.
0s

Not sure why??? It looks fine?

[animate1978]

More bugs related to the Hair presets

Traceback (most recent call last):
  File "/home/farishta/.config/blender/2.81/scripts/addons/MB-Lab/__init__.py", line 596, in hair_style_list
    fileName = hairengine.get_hair_npz('CY_shader_presets.npz')
AttributeError: module 'MB-Lab.hairengine' has no attribute 'get_hair_npz'
File "/home/farishta/.config/blender/2.81/scripts/addons/MB-Lab/__init__.py", line 593, in hair_style_list