Add resolved expressions recursively up the context chain

[jmp3833]

Rather than using addResolvedFrom to combine resolved expressions from multiple Context objects, it would be more widely applicable to recursively add resolved expressions up the parent context chain. This way information isn't lost when rendering a nested structure, with multiple nested contexts and resolved expressions.

@boulter do you think this would be worth applying to Context's resolved functions and values as well?

cc @hs-lsong

[hs-lsong]

Does jinjava has the concept of scope? If so, a child's expression may not be the same as the parent's. I do not have the context of this issue. Why do we need this?

[boulter]

I agree that we should do the same for function and variables too.

[jmp3833]

@hs-lsong currently the Context objects aren't scoped, but a nested set of expressions will have a Context object applied to each expression. We would like the ability to traverse the entire collection of resolved expressions of any Context object from the root Context.

This way we can perform selective logic if we detected a certain resolved expression, function, or value after processing a large chunk of text with JinJava. We had been using the addResolvedFrom function to apply values up the context chain but rather than doing this on a case by case basis, it would be nice to have all of these values applied to the root Context all the time.