create Materials tag if it isn't present (old schematics)
create Materials tag if it isn't present (old schematics)

ahh2131/mchisel,codewarrior0/pymclevel,mcedit/pymclevel,ahh2131/mchisel,arruda/pymclevel,codewarrior0/pymclevel,mcedit/pymclevel,arruda/pymclevel