Initial framework with Elasticsearch

[osma]

The first version of the framework should have

• a Flask app that can be started using "flask run"
• a command "flask init" that creates the repository for projects in Elasticsearch
• tests for the above, running within Travis CI

[osma]

The index name used to store information about projects should be configurable using the normal Flask mechanisms. There should be a "project" type with attributes similar to those in the projects.ini configuration in the prototype, i.e. project name, language and ES analyzer. The index name could probably be autogenerated from the project name, so no need to store it separately. (Corpus pattern is only relevant for loading operations, not necessary here)