- Global APREQ_COOKIE_MAX_LENGTH  
- convert this macro to an apreq_module_t method.
 
 
- Global apreq_atoi64f  
- What happens when s is malformed? Should this return an unsigned value instead? 
 
- Global apreq_atoi64t  
- What happens when s is malformed? Should this return an unsigned value instead? 
 
- Global apreq_brigade_concat  
- Flesh out these error codes, making them as explicit as possible.