Fix youtu.be regex so it supports capital letters and properly escapes hyphens.
Fix youtu.be regex so it supports capital letters and properly escapes hyphens.

enfold/tinymce,TeamupCom/tinymce,gabixdev/tinymce,jtark/tinymce,adaptiffdesigns/tinymce,leofeyer/tinymce,henrythewasp/tinymce,howanghk/tinymce,ice8lue/tinymce,MediehusetTek/tinymce,tinymce/tinymce,adaptiffdesigns/tinymce,nbcp/tinymce,Zimbra/tinymce,fhchina/tinymce,rxl194/tinymce,pmpl-5/tinymce,Razzwan/tinymce,rednose-public/tinymce,blakewallan/tinymce,support-dot-com/tinymce,Shopify/tinymce,bsuh/tinymce,henrythewasp/tinymce,danielpunkass/tinymce,jtark/tinymce,FernCreek/tinymce,VioletLife/tinymce,kencheung/tinymce,Kindling/tinymce,danchr/tinymce,tinymce/tinymce,endjin/tinymce,fashionsun/tinymce,VioletLife/tinymce,dziemian007/tinymce,shilpi230/tinymce,sachgits/tinymce,enfold/tinymce,support-dot-com/tinymce,ETSI-CTI/TinySpecMCE,dziemian007/tinymce,gencer/tinymce,sachgits/tinymce,danielpunkass/tinymce,TeamupCom/tinymce,blakewallan/tinymce,sjbufton/tinymce,ice8lue/tinymce,gencer/tinymce,rxl194/tinymce,FernCreek/tinymce,ikuchmin/tinymce,shilpi230/tinymce,simachewh/tinymce,tinymce/tinymce,danchr/tinymce,fashionsun/tinymce,1099511627776/tinymce,Razzwan/tinymce,1099511627776/tinymce,danielpunkass/tinymce,howanghk/tinymce,MediehusetTek/tinymce,aduth/tinymce,pmpl-5/tinymce,aduth/tinymce,nikolas/tinymce,nbcp/tinymce,ikuchmin/tinymce,bsuh/tinymce,Zimbra/tinymce,FernCreek/tinymce,gabixdev/tinymce,kencheung/tinymce,jashua212/tinymce,rbecheras/tinymce,nikolas/tinymce,sjbufton/tinymce,leofeyer/tinymce,M4R7iNP/tinymce,ChristophKaser/tinymce,jashua212/tinymce,fillabs/TinySpecMCE,ETSI-CTI/TinySpecMCE,simachewh/tinymce,rbecheras/tinymce,fillabs/TinySpecMCE,ChristophKaser/tinymce,Kindling/tinymce,rednose-public/tinymce,M4R7iNP/tinymce,endjin/tinymce,fhchina/tinymce