Batch resize .svg files
Looks like the -fit option on this command line utility will do exactly what you want: 

https://github.com/vieron/svg-resizer 

If you need help with brew, look here: http://coolestguidesontheplanet.com/installing-homebrew-os-x-yosemite-10-10-package-manager-unix-apps/ 

If your not comfortable with the command line, don't let it intimidate you - it's really not that hard.  Post back if you get stuck or something just doesn't make sense.