Use cross-platform way to determine calling file.
Use cross-platform way to determine calling file.

':' are used to separate drive letters from paths on Windows
Replace simple split functionality with basic Regexp.

Thanks to Obie for his regular expression knowledge.

Signed-off-by: Yehuda Katz <6cca45edf25d9f6c44ec8f2aa59ba63f92457e1b@gmail.com>
sideci-sample/sideci-sample-thor,groovenauts/thor,fhernandez173/thor,frsyuki/bundler,roseweixel/bundler,schaary/bundler,h4ck3rm1k3/bundler,trampoline/bundler,mvz/bundler,sideci-sample/sideci-sample-thor,shaiguitar/thor,bronzdoc/bundler,patvice/bundler,anil826/bundler,bundler/bundler,jasonkarns/bundler,doudou/thor,sideci-sample/sideci-sample-bundler,linkodehub/thor,roseweixel/bundler,EasonYi/bundler,groovenauts/thor,mpapis/bundler,davydovanton/bundler,jingweno/bundler,asymmetric/bundler,nju520/bundler,fhernandez173/thor,r7kamura/bundler,byroot/bundler,jaym/bundler,RochesterinNYC/bundler,byroot/bundler,danimashu/bundler,mdorrance/bundler,ligi/bundler,wenderjean/bundler,christer155/bundler,nju520/bundler,gregkare/bundler,JuanitoFatas/bundler,CorainChicago/bundler,erikhuda/thor,christer155/bundler,ligi/bundler,flyinbutrs/thor,jingweno/bundler,rkh/bundler,wenderjean/bundler,CorainChicago/bundler,zhangkuaiji/bundler,tgxworld/bundler,asymmetric/bundler,lmtim/bundler,mpapis/bundler,b-dean/thor,gregkare/bundler,agis-/bundler,chef/bundler,philnash/bundler,danimashu/bundler,b-dean/thor,lmtim/bundler,elovelan/bundler,kohgpat/bundler,carpodaster/bundler,gentoo/bundler,frsyuki/bundler,simplybusiness/bundler,dilumnavanjana/bundler,mvz/bundler,asutoshpalai/bundler,ximus/bundler,MasterLambaster/bundler,Wirachmat/bundler,drnic/thor,PG-kura/bundler,schaary/bundler,ximus/bundler,Eric-Guo/bundler,agis-/bundler,chulkilee/bundler,cstrahan/bundler,seanlinsley/bundler,steved/bundler,patvice/bundler,chef/bundler,suhastech/bundler,RochesterinNYC/bundler,masarakki/bundler,TimMoore/bundler,r7kamura/thor,raphael/bundler,seanlinsley/bundler,r7kamura/thor,smlance/bundler,ngpestelos/bundler,steved/bundler,Elffers/bundler,Elffers/bundler,Wirachmat/bundler,haonature888/bundler,AiyionPrime/bundler,robinboening/bundler,cdwort/bundler,TimMoore/bundler,Teino1978-Corp/Teino1978-Corp-bundler,anil826/bundler,Flameeyes/bundler,haonature/bundler,masarakki/bundler,fancyremarker/thor,lgierth/bundler,dilumnavanjana/bundler,cowboyd/bundler,pjump/bundler,twcctz500000/bundler,joshsoftware/bundler,bundler/bundler,mtscout6/bundler,mdorrance/bundler,simplybusiness/bundler,jasonkarns/bundler,EthanK28/bundler,ipmobiletech/bundler,joshsoftware/bundler,1337807/bundler,suhastech/bundler,carpodaster/bundler,mattbrictson/bundler-1,fancyremarker/thor,e2/bundler,ngpestelos/bundler,haonaturel/bundler,cdwort/bundler,zhangkuaiji/bundler,robinboening/bundler,vemmaverve/bundler,neslom/bundler,kohgpat/bundler,EasonYi/bundler,PG-kura/bundler,asutoshpalai/bundler,Teino1978-Corp/Teino1978-Corp-bundler,pivotal-cf-experimental/bundler,cstrahan/bundler,linkodehub/thor,haocafes/bundler,ducthanh/bundler,h4ck3rm1k3/bundler,pivotal-cf-experimental/bundler,segiddins/thor,EthanK28/bundler,tgxworld/bundler,jaym/bundler,smlance/bundler,sideci-sample/sideci-sample-bundler,flyinbutrs/thor,neslom/bundler,elovelan/bundler,mattbrictson/bundler-1,davydovanton/bundler,chulkilee/bundler,ipmobiletech/bundler,bronzdoc/bundler,eagletmt/bundler,Eric-Guo/bundler,segiddins/thor,pjump/bundler,philnash/bundler,AiyionPrime/bundler