minor; fix for empty strings interpolation
Merge branch 'master' of https://github.com/apla/dataflo.ws
Merge branch 'master' of https://github.com/apla/dataflo.ws

Conflicts:
	workflow.js
Merge branch 'master' of https://github.com/apla/dataflo.ws
added feature to run flow from callback initiator
new version 0.0.39
Merge branch 'master' of https://github.com/apla/dataflo.ws