Update API.md
Update API.md

Added a bit more info around 'src' and 'dst'.
caseytrombley/gulp,jhsu/gulp,codeclimate-demo/gulp,mohislm/gulp,breyed/gulp,lanbin/gulp,ruspython/gulp,JimiHFord/gulp,bORm/gulp,Tiger66639/gulp,es128/gulp,nmccready/gulp,Tiger66639/gulp,lcoder/gulp,benweet/gulp,pdehaan/gulp,MarcBT/gulp,huzion/gulp,hckhanh/gulp,sonjudan/gulp,imjerrybao/gulp,tkvern/gulp,pdg6805/gulp,silverbux/gulp,soliury/gulp,geltoncruz/gulp,stevemao/gulp,duanying0818/gulp,AlexKomrakov/gulp,klausbayrhammer/gulp,JsAaron/gulp,JsAaron/gulp,IrvBriscoe/gulp,cgourlay/gulp,foresthz/gulp,yonglehou/gulp,brilliun/gulp,michaelgena/gulp,preco21/gulp,ybg555/gulp,tuzilingdang/gulp,Teino1978-Corp/Teino1978-Corp-gulp,prashant-andani/gulp,jonsterling/gulp,mohislm/gulp,bORm/gulp,demohi/gulp,prashant-andani/gulp,XiaoLongW/gulp,anorthwolf/gulp,iSC-Labs/gulp,ged/gulp,jaeh/gulp,cgvarela/gulp,Coaxial/gulp,donglegend/gulp,snidima/gulp,romario333/gulp,eaglesjava/gulp,gavioto/gulp,vineethawal/gulp,pdehaan/gulp,thejameskyle/gulp,mariuszskon/gulp,tksander/gulp,chrismoulton/gulp,frankwallis/gulp,Zagorakiss/gulp,liangzhien/gulp,KillerDesigner/gulp,IrvBriscoe/gulp,jonsterling/gulp,ybg555/gulp,ankita-kumari/gulp,moander/gulp,crspiccin/gulp,romario333/gulp,yochannah/gulp,AleksueiR/gulp,Zagorakiss/gulp,xuxinpie/gulp,ruspython/gulp,gavioto/gulp,yugle7/gulp,aaron-goshine/gulp,silverbux/gulp,es128/gulp,MichaelFBA/gulp,wjb12/gulp,seedtigo/gulp,zpao/gulp,flackend/gulp,jmm/gulp,tkvern/gulp,BogusCurry/gulp,fengjianjunstudy/gulp,MichaelFBA/gulp,zpao/gulp,SimenB/gulp,r14r/fork_javascript_gulp,ankita-kumari/gulp,borellaster/gulp,ancchaimongkon/gulp,gulpjs/gulp,midgethoen/gulp,huzion/gulp,pppp22591558/gulp,borellaster/gulp,yochannah/gulp,tuzilingdang/gulp,fengjianjunstudy/gulp,youprofit/gulp,jaeh/gulp,maxhollmann/gulp,tfennelly/gulp,cgourlay/gulp,AtChina/gulp,SimenB/gulp,yugle7/gulp,seedtigo/gulp,stoeffel/gulp,wjb12/gulp,zongkelong/gulp,flackend/gulp,iSC-Labs/gulp,caseytrombley/gulp,maxhollmann/gulp,kt3k/gulp,mikehaas763/gulp,mad-aran/gulp,liangzhien/gulp,yonglehou/gulp,zensh/gulp,codeclimate-demo/gulp,thejameskyle/gulp,PNW3DEV/gulp,lcoder/gulp,GoodBoyDigital/gulp,mikehaas763/gulp,Coaxial/gulp,tfennelly/gulp,wbinnssmith/gulp,donglegend/gulp,jmm/gulp,Rorchach/gulp,rlugojr/gulp,aaron-goshine/gulp,preco21/gulp,ged/gulp,midgethoen/gulp,Teino1978-Corp/Teino1978-Corp-gulp,ajwebb/gulp,breyed/gulp,imjerrybao/gulp,mad-aran/gulp,irenekay/Gulpjs-Webtest,geltoncruz/gulp,duanying0818/gulp,VANITAX/gulp,chrismoulton/gulp,hckhanh/gulp,JimiHFord/gulp,GoodBoyDigital/gulp,callumacrae/gulp,nmccready/gulp,cgvarela/gulp,sttk/gulp,edisplay/gulp,pH200/jsrun,PNW3DEV/gulp,ancchaimongkon/gulp,MarcBT/gulp,pH200/jsrun,vineethawal/gulp,bobintornado/gulp,jhsu/gulp,foresthz/gulp,BogusCurry/gulp,AtChina/gulp,soliury/gulp,rlugojr/gulp,brilliun/gulp,AleksueiR/gulp,mariuszskon/gulp,edisplay/gulp,tksander/gulp,songshuang00/gulp,benweet/gulp,pdg6805/gulp,stevemao/gulp,michaelgena/gulp,pppp22591558/gulp,zensh/gulp,eaglesjava/gulp,snidima/gulp,anorthwolf/gulp,wbinnssmith/gulp,VANITAX/gulp,frankwallis/gulp,lanbin/gulp,doginthehat/gulp,zongkelong/gulp,ajwebb/gulp,songshuang00/gulp,doginthehat/gulp,moander/gulp,r14r/fork_javascript_gulp,minodisk/gulp,crspiccin/gulp,xuxinpie/gulp,Rorchach/gulp,klausbayrhammer/gulp,minodisk/gulp,KillerDesigner/gulp,bmds/gulp,AlexKomrakov/gulp,youprofit/gulp,bobintornado/gulp,callumacrae/gulp,bmds/gulp,sonjudan/gulp,XiaoLongW/gulp