refactor caller_files
refactor caller_files

- supports external modification of ignores list (e.g. to include polyglot)
- provides additional caller_locations method to include line numbers (e.g. for render backtraces)

guidohcosta/sinatra,burningTyger/sinatra,emiliocorpus/sinatra,davydovanton/sinatra,ganmacs/sinatra,ABaldwinHunter/sinatra-classic,trexnix/sinatra,ryanshaw/sinatra,gferguson-gd/sinatra,blambeau/sinatra,siberianbear/sinatra,ktw1222/sinatra,nju520/sinatra,sinatra/sinatra,twanies/sinatra,howtolearntocode/sinatra,ABaldwinHunter/sinatra-classic,miyazawatomoka/sinatra,porras/sinatra,Rayheng/sinatra,burningTyger/sinatra,wzheng1/sinatra,nju520/sinatra,JonMidhir/sinatra,kgrz/sinatra,wzheng1/sinatra,JonMidhir/sinatra,nottombrown/old-sinatra,gferguson-gd/sinatra,Wirachmat/sinatra,jkowens/sinatra,laplaceliu/sinatra,davydovanton/sinatra,jenalgit/sinatra,JonMidhir/sinatra,jenalgit/sinatra,bmizerany/sinatra,kyontan/sinatra,miyazawatomoka/sinatra,dariubs/sinatra,kumji/sinatra,guidohcosta/sinatra,twanies/sinatra,siberianbear/sinatra,nicoayala/sinatra,JonRowe/sinatra,kyontan/sinatra,frechei/sinatra,sinatra/sinatra,QLGu/sinatra,QLGu/sinatra,Wirachmat/sinatra,mwpastore/sinatra,defsprite/sinatra,howtolearntocode/sinatra,jkowens/sinatra,Rayheng/sinatra,autopp/sinatra,DoraALin/sinatra,burningTyger/sinatra,kumji/sinatra,laplaceliu/sinatra,ktw1222/sinatra,sethuster/sinatra,porras/sinatra,mwpastore/sinatra,nottombrown/old-sinatra,ryanshaw/sinatra,lastcat/sinatra,ksw2599/sinatra,ksw2599/sinatra,JonRowe/sinatra,marocchino/sinatra,Callygraphy/morrissey,jkowens/sinatra,trexnix/sinatra,mwpastore/sinatra,sethuster/sinatra,RosenDimov/sinatra,midorineko/sinatra,DoraALin/sinatra,cyberid41/sinatra,emiliocorpus/sinatra,cyberid41/sinatra,ganmacs/sinatra,midorineko/sinatra,d-bot/sinatra,autopp/sinatra,frechei/sinatra,dariubs/sinatra,eileencodes/sinatra,nicoayala/sinatra,defsprite/sinatra,eileencodes/sinatra,RosenDimov/sinatra,lastcat/sinatra,d-bot/sinatra