lib/svg2js: catch and output xml parser errors (fix #4)
lib/svg2js: catch and output xml parser errors (fix #4)

ennett50/svgo,WebTwist/svgo,bORm/svgo,OrangeLV/svgo,pgherveou/svgo,pieter-lazzaro/svgo,akatopo/svgo,ricardobeat/svgo,svg/svgo,ben-eb/svgo,allypalanzi/svgo,svg/svgo,jagan-veeraraghavan/svgo,subzey/svgo,PeterWangPo/svgo