Implementation of a HyperFlow server providing REST API for workflows.
Implemented API operations in this version:
- creation of a new workflow instance
- sending signals to a workflow instance
Implemented distributed workflow execution, see script
"test/restapi_test.sh"
Workflows used in the distributed workflow execution test.
Minor update.
Corrections in comments
Added implementation of a few GET operations.
Merge branch 'feature/restapi' of https://github.com/dice-cyfronet/hyperflow into feature/restapi
Delete outdated montage.test.js

Generic script scripts/runwf.js should be used to run workflows.
Delete wfchoice.test.js

Generic script scripts/runwf.js should be used to test workflow runs. Initial input signals can now be placed directly into workflow json file.
Delete splitter.test.js

Now generic script 'scripts/runwf.js' should be used to run workflows. Initial signals can be set directly in the workflow file.
Delete sqrsum.test.js

Generic script 'scripts/runwf.js' should be used to run workflows. Initial signals can be set directly in the workflow file.
Delete engine.test.js
Delete dax.test.js
Merge branch 'feature/restapi' into develop

Conflicts:
	functions/index.js
	package.json
	wflib/index.js
Switched to new Engine implementation