Use JS/Python prototype instead of conditions to choose the correct JS <=> Brython conversion method

[denis-migdal]

Enable users to declare new JS <=> Brython conversions without any additional cost to the conversion functions.
It enables to delegate this responsibility making conversions functions more clear/readable.

It doesn't seem to have a big impact on performances when using the test suite ?
I'll fix the server.py CGI to see the speed test report.

$B.addPy2JSWrapper(pyclass, function(pyobj) {
	
        return .... // return your jsobj
});

$B.addJS2PyWrapper(JSClass, function(jsobj) {
        return ... // return your pyobj
});

[PierreQuentel]

Sorry Denis, I won't accept this PR. Conversion to and from Javascript should not be included in py_dict.js, py_string.js and the like, these scripts are implementation of the Python objects.

The interface between Brython and Javascript is only a part of the Brython project, and one I don't give a huge importance to: I am more interested in providing tools to write client-side programs without having to write in Javascript.

All or most of the JS/Brython interface should remain in js_objects.js.

[denis-migdal]

So should I make a commit moving them to js_objects.js ?

[PierreQuentel]

So should I make a commit moving them to js_objects.js ?

Yes, please.

[denis-migdal]

Yes, please.

Done. I can't move the one for DOMNode as it is defined after execution of js_object.js.

I added a "description", so that we can have an overview on the convertions being made.

@PierreQuentel what should be the next step ?