This is a breaking change for users that may rely on `assets/bpmn-font`
being present in the library.
BREAKING CHANGE:
* use `bpmn-font` package, specifically `bpmn-font/dist` if you need the
font previously contained in the assets directory.
This renames distribution files to:
{variant}.development.js
{variant}.production.min.js
Additional changes:
* drops .map file; users should use .development bundle
for easier debugging
Related to #725
BREAKING CHANGE:
* distribution files have been renamed; users must update their
apps accordingly if they'd like to use newer bpmn-js dists
Reduces the size of bpmn-js {Viewer, NavigatedViewer, Modeler}
bundles by roughly eight percent:
* module concat / tree-shake produced production bundle
* bump diagram-js version to fix <this> used in ManhattanLayout
utility