Join sources with interpolation
Join sources with interpolation

JRuby's String#join doesn't respect encodings

Fixes #47
colindean/execjs,universsky/execjs,colindean/execjs,golla/sample1,looker/execjs,sstephenson/execjs,atambo/execjs,ibroadfo/execjs,sstephenson/execjs,rails/execjs,atambo/execjs,universsky/execjs,lunks/execjs,maclover7/execjs,golla/sample1,maclover7/execjs,rails/execjs,lunks/execjs,ibroadfo/execjs,colindean/execjs,looker/execjs