Added some documentation to XML output archive describing how it works.
Added attribute size="dynamic" to types that specify a size tag for XML, making it easier for a human to figure out what
they can add or remove data from.
Documentation updates on a few other things.
type traits were failing on T& as opposed to a T. loading's processimpl now only takes refs. we still let op() take
r-values in case someone passes it an nvp or something
Added more NVP info to types that need it
Adding ability to detect a save function (member or non-member) that is incorrectly declared as non-const. This is
needed since some nasty compilation errors crop up if you explicitly specify a serialization type and register that type
with an incorrectly constified save function.
So not done yet, but soon in: using a non const save function will trigger a static assertion.
Still need to investigate registering types with explicit disambiguation
