dirTagbox: Added optional callback and two fixes
dirTagbox: Added optional callback and two fixes

Fixed regex which did not work as expected when no tag token had been
specified. Also moved the startsWith filter inside this module.

phw/angularUtils,allanlb/angularUtils,tianhengzhou/angularUtils,danlobo/angularUtils,zzzzzyuzhang/angularUtils,Git1111/angularUtils,jlgrock/angularUtils,romelgomez/angularUtils,benoror/angularUtils,wpsmith/angularUtils,dszmaj/angularUtils,pkdevbox/angularUtils,yshyee/angularUtils,humpy125/angularUtils,saike/angularUtils,pkdevbox/angularUtils,jlgrock/angularUtils,narasingh/angularUtils,michaelbromley/angularUtils,allanlb/angularUtils,humpy125/angularUtils,kzganesan/angularUtils,Kerruba/angularUtils,zzzzzyuzhang/angularUtils,phw/angularUtils,radhikagiri/angularUtils,saike/angularUtils,tianhengzhou/angularUtils,imakmgit/angularUtils,michaelbromley/angularUtils,telesma/angularUtils,radhikagiri/angularUtils,Kerruba/angularUtils,noahxinhao/angularUtils,benoror/angularUtils,dszmaj/angularUtils,yshyee/angularUtils,alexkuttig/angularUtils,kzganesan/angularUtils,Git1111/angularUtils,telesma/angularUtils,wesleyliu/angularUtils,romelgomez/angularUtils,imakmgit/angularUtils,danlobo/angularUtils,noahxinhao/angularUtils,wpsmith/angularUtils,alexkuttig/angularUtils,wesleyliu/angularUtils,narasingh/angularUtils