initialize Port#model with an empty model if none is available
make NameService#each_task return an enum if no block is given
webapi: start implementing a REST API using Grape
webapi: update after the implementation of the proper typelib-to-json API in typelib
webapi: require that all task names are given in full (i.e. with namespace)
webapi: define the tasks/:namespace/:name/ports endpoint
webapi: implement a streaming mode to read a port
webapp: implement a command-line tool to start the webapp server
update manifest.xml to include the packages that the webapp requires
webapp: rename 'webapi' to webapp

Given the plans I have for the thing (including a model
presentation in HTML, integrating process server functionality,
serving mix of static HTML and javascript to display data),
the term "webapi" is too limited. Rename to webapp