Basically this is supposed to set node's content in a way similar to how attributes are set. Currently when you call a method on a builder instance it checks whether an attribute named as the method exists. If not it creates a child node with that name. However if you need to create a node with text content and an attribute you don't want a child node to be created, so you can call this method to set node's content.

It's actually related to the way we're using `Lolsoap::Builder` in our code: we transform a hash that contains both attributes and child nodes into an xml document by traversing the hash and sending key/value pairs to a builder instance. In that code we don't try to separate attributes from child nodes, so I thought that setting content should work in a similar way and lolsoap should handle it as it does with attributes.