* Note that while this is public and uses std::string, because it's a
template with specialisations in a .inl the string never crosses a
module boundary - each including module has its own implementation.
* This will be used as part of the upcoming serialisation refactor.
* Some POD structs are still given ToStr implementations as we haven't
yet switched over the serialisation system to expect all structs to
have serialise functions.
* We have some special handling to allow SWIG wrapping of these types:
SDFile owns the chunks and buffers within, and each object owns its
children. Copying is disallowed except from SWIG where we assume the
wrapper is handling lifetime management for its objects externally.
* Previously we would convert from python to C++ arrays immediately by
copying, and vice-versa convert TO python immediately by creating a
new python list by copying.
* This however behaves rather poorly in common situations, e.g.:
> foo.bar.append(5)
Would not append 5 to foo.bar, but copy foo.bar to a temporary, append
5 to it, then destroy it leaving foo.bar untouched.
* Instead we leave the C++ array type as a pointer for as long as we can
and instead implement the python sequence API as extensions/slots that
work in-place on the original array.