Add a slight flaring to the clips holding the filter holder to the filter box

[mechatroniks-git]

getting the clips to attach to the boxes with foam in between is challenging and requires extra, potentially damaging, pressure be put on the weather guard to squeeze the halves together. A slight flaring at the top of the clip should help ease the clips on.

[mmroden]

Closing as "won't do", we won't be using clips