#176 Removed outcommented code
#176 Replaced usage meta::get_ptr
#176 Removed istype function
#176 Removed meta::get_ptr
#176 Removed NATIVERETURN macro
#176 Replaced templated meta::isa with non-templated is_a
#176 Pointer instead of reference in meta::as
#176 Pointer instead of reference in meta::as_vector
#176 Fixed bug in %meta_pair