plugins/convertPathData: global refactoring, fix #22 + fix #23
plugins/convertPathData: global refactoring, fix #22 + fix #23

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