* use ES6 import / export
* UTILS: export individual utilities
* TESTS: localize TestHelper includes
BREAKING CHANGE:
* all utilities export independent functions
* library sources got ported to ES6. You must now use
a ES module bundler such as Browserify + babelify or
Webpack to consume this library (or parts of it).
This commit adds the ModelingFeedback component. It hooks into
modeling action rejected events and displays error messages
to the user.
The current behavior is to show an error message when dropping
a flow node outside a participant in a collaboration.
Related to #203