[WIP] put scheduling solution.
Refactor the Client to make requests lazily.
Update alf-core and add rack-robustness dependency.
Always require json
Refactor UpdateSchedulingSolution, removed `fixed` and `last_xxx`.
Move Alf helpers up in the class hierarchy.
Add ability to PUT on the testing client.
Add web service to install a dataset in testing environment.
Require time on testing client.
Add formal support for resources, their type and decoding.
Add a rack-robustness shield in the web stack.
Implement PUT /scheduling/solution.
Implement optional "tuple" attributes with "multi tuples type"
Mark some doses as optional.
Check the validity of resources on JSON output.
Releasing v0.4.0