[SofaPython3] Changes how addObject process its arguments when they are of type: numpy & data

[damienmarchal]

The PR changes how addObject is handling some parameter according to their type.

numpy array

When passing a numpy array to the addObject simply does not work reporting an unparsable string.
Eg:

node.addObject("MeshObjLoader", name=loader)
node.addObject("MechanicalObject", position=node.loader.position.value)

This does not work because position.value is of type numpy and that the object creation is trying to do a string conversion (which does not returns string parsable by Sofa). The PR detect numpy arrays and implement the proper conversion.

Data fields

When passing a BaseData object to the addObject the current implementation is copying the data.
Eg:

node.addObject("MeshObjLoader", name=loader)
node.addObject("MechanicalObject", position=node.loader.position)

It was discussed in #197 what should be the most appropriate scenario.
This PR implement the following scenario:

defcreateScene(root):
root.addObject("MeshObjLoader", filename="mesh/cube.obj", name="loader");
a=root.addObject("PointSetTopologyContainer", position=root.loader.position.linkpath, name="topo") # explicitly makes a linkb=root.addObject("PointSetTopologyContainer", position=root.loader.position.value, name="topo") # explicitly makes copyc=root.addObject("PointSetTopologyContainer", position=root.loader.position, name="topo") # implicitly makes a link 

It is yet undecided if we prevent the implicit version, and if we keep it if it should makes a link or a copy.

NB: the tests for linkpath will fails until the following sofa PR: sofa-framework/sofa#2354
is not merged.

[damienmarchal]

tests are passing now (not the one with 21.06...but this is expected)

[hugtalbot]

it works for me ! 👍
I will add this in the SP3 doc !

[damienmarchal]

I remember a long time ago there was a rule saying that a PR without a "no go message" for more than seven days were considered as ready to merge.

This one is on-hold for 19 days now.

[damienmarchal]

@hugtalbot, @fredroy the changes requested are done.