Type introspecion

[ugeorge]

This fork adds the following features:

• traversal/introspection methods for template-based (C++) structures.
• XML dumper for introspective types
• traversal/getter methods + helpers for accessing C types inside C++ structures by means of passing indexes as argument packs.
• helper macros for removing boilerplate in typedefs, struct, union and all the auxiliary functions (defining streams, introspection names, etc...)