Adding a helper function to calculate log base 2 as constexpr; renaming rosa/support/types.hpp to rosa/support/type_helper.hpp; adding some convenience type definitons in rosa/support/types.hpp: unit_t, none_t, Optional; adding various type-related facilities under rosa/support: TypePair, TypeList, SquashedInt; defining a static list of types identified as BuiltinTypes containing types that are intended to be used in messages and places that may require value serialization eventually (rosa/support/type_numbers.hpp); defining a static unique representation of lists of builtin types with integer values of type token_t, for encoding type information of tuples in compile-time and efficiently checking/matching them in runtime (rosa/support/type_token.hpp); adding an example type-facilities that briefly demonstrates the defined type numbering and encoding features.