COVID19 Headband x4 stack with improved adhesion and support

CHANGELOG: 4/2/2020: Updated the model to have more support between bands. This makes it a little harder to pull apart, but ensures that the bands adhere well to each other, as I found that some layers would not adhere and cause stringing or print failures. DESCRIPTION: This is a remix of the x4 stacked covid19 prusa RC3 headbands. I found the model was missing some support structure and the supports were likely to lose bed adhesion. I fixed the missing support structure and added a brim to the support sections to improve bed adhesion.