bin icons not loaded by default

The fzb files are set with the icon as 'custom.png', I had to change it to the actual bin icons name in a text editor and put all the icons in the same folder to get them to show.

Locate the affected .fzb files and inspect their icon references, especially entries set to "custom.png". Compare those references with the bin icon files in the same folder and verify the parts load their intended icons by default in Fritzing.

Written by the indexing model from the issue text.