Custom icons creator

[jet app]

Hi guys

I'm trying to create simple flat custom icons for my app. I've already tried Vectornator and Gravit to make svg file. However I get stuck on converting it to fonts on http://fluttericon.com I get an error If image looks not as expected please convert to compound path manually. Skipped tags and attributes: stroke,stroke-width,fill,stroke-linecap,opacity,stroke-linejoin   I know I will have to modify somehow that parameters but just because I need to make quite a lot of these icons I really do not want to modify these parameters on each of them. Is there any simple program for icons which would save the svg file with correct parameters ready for fluttericon.com without me messing with the file?

Thanks in advance