Circular element references inside wsdl - assistance needed

[doubleaxe]

Hello.

This fix #1101 fixed one bug and introduced another. Now parsing wsdl with recursive ref elements will cause stack overflow. I created 2 test cases which demonstrate this bug, but I need advice of someone who knows this project better than me.

I can quick fix stack overflow with one kludge - just like #1101, something like this, or maybe a little more complex - because second test will fail with this:

          if (!this.$ref) {
            definitions.descriptions.types[typeName] = elem;
          } else {
            const refType = splitQName((typeElement as ElementElement).$type);
            if(refType.name != typeName)
              definitions.descriptions.types[typeName] = elem;
          }

As pedantic person, I think kludge is not the way to do. In my opinion main problem is more deep in internals: both element names (with references) and type names go to the same object definitions.descriptions.types, they are mixed, and this introduces all these bugs with elements and types, but I'm not sure in this, because I'm new to node-soap internals, I just use it as a regular user.

So I need advice from someone, I can try to fix this by splitting definitions.descriptions.types for elements and for types, but it seems this is core internal feature, I'm afraid to break something and waste my time making PR which will not be accepted.

[coveralls]

Coverage remained the same at 95.019% when pulling e588d8c on doubleaxe:recursive_wsdl_ref_bug into bf3b07d on vpulim:master.

[doubleaxe]

I updated PR, this is my vision on how this bug should be fixed. All tests seems passing, I only doubt in backward compatibility.