Modified IC3D face shield frame

Modify the IC3D face shield design (https://3dprint.nih.gov/discover/3dpx-013309). Fix a few mesh errors that might be problematic for some slicers. Replace the original strap holes with a new one from the Brazil HeadBand design. Also reduce the unnecessary height to save filament.

This face shield is good in that it completely covers the top for more protection. However it uses more filament and is also quite rigid to wear.