Add tests for base64 stream
Add tests for base64 stream

rafaeldelucena/waterbutler,hmoco/waterbutler,Johnetordoff/waterbutler,kwierman/waterbutler,Ghalko/waterbutler,CenterForOpenScience/waterbutler,chrisseto/waterbutler,felliott/waterbutler,TomBaxter/waterbutler,cosenal/waterbutler,icereval/waterbutler,rdhyee/waterbutler,RCOSDP/waterbutler