added support for extensions to Globalize2, via callbacks
added support for extensions to Globalize2, via callbacks

aalfson/globalize,benhutton/globalize3,reevoo/globalize3,gaganawhad/globalize-cache-key,Buyapowa/globalize,goarch/globalize,rdutra/globalize3,joshmh/globalize2,2947721120/globalize,tuv/globalize3,LyriD/globalize3,trongrg/single_table_globalize3,ASnow/globalize,andreazaupa/globalize3,DaveahamLincoln/globalizer_refinery_patch,awernick/globalize,distribusion/globalize,eet-nu/globalize3,mysociety/globalize