Decode algorithm prototype content if python is older than 3.6

Closes #71

See merge request !61

Fixes #71

ZMQ architecture documentation

Closes #70

See merge request !60

The some of the commands described here were for the V1 API.

Move license to BSD 3 Clause

Closes #60

See merge request !59

Fixes #60

Worker: decode recieved job data if python older than 3.6

See merge request !58

Prior to 3.6 the json module handles only str types. After that
more types are supported out of the box.

Fix docker-pull implementation

See merge request !57

[test][test_docker] Increase a bit more the container memory for the memory-limit test (maybe a py3 requirement?)

This commit resets the container memory limit on the memory-limit test
to a higher value.  It turns out that Docker-18.09 is complaining it
cannot set the memory of the container in question to 4 Mb, possibly
because it starts up with more than that memory already (see discussion
about this here:
https://unix.stackexchange.com/questions/412040/cgroups-memory-limit-write-error-device-or-resource-busy).  Increasing the container memory to 10 Mb
and to the allocated array to 20 Mb makes the test work again.

Make default dataformat search look for more types on algorithm prototype load

Closes #67

See merge request !56

The test prefix and generated platform prefix have two different
content, therefore, search for both integer and integers to ensure
one is found at run time.

Fixes #67

Algorithm schema update

See merge request !52

When a new algorithm is created the prototype is used to generate
the new object. In order to comply with the new fixed version of
the schema (inputs and outputs must has at least one value), the
prototype must also have one of each. Since the dataformat used
is also validated as part of the creation, it must exist on the
platform. In order to ensure that we are using a valid dataformat,
the "integers" format is used and searched in the prefix to ensure
the correct author is used as it might be different depending on
how the platform was setup.

Re-enable nitpicky mode and Fix broken docs

See merge request !54

Zmq refactoring

See merge request !53

Store the returned value and check that we have what we
wanted.

https://docs.python.org/3/library/multiprocessing.html?highlight=qsize

The BEAT computation being fully asynchronous, the client does
not expect immediate reply to its requests. Therefor this
warning is misleading.

Unlike the Majordomo ZMQ example, we have "single" workers with work
assigned and possible actions taken on arrival/departure. Therefore
the purge should check the whole list to ensure that everything is
done with respect to the status of the worker.

This implements a new paradigm for the process nodes
communication. Based on the ZMQ Majordomo protocol,
its goal is to improve reliability of the setup.

Add automatic test image pulling if not already available (closes #63)

Closes #63

See merge request !51