Stdlib compat

This is missing tests and documentation but I'd like to get some comments on it. 
The IPADD general name is either a 4 bytes (IPv4) or 16 bytes (IPv6) sequence.  For constrains the values are 8 or 16 bytes for a IPv4 or IPv6 network with mask. GENERAL_NAME_print() prints GEN_IPADD as "IP Address:1.2.3.4" or "IP Address:8:9:A:B:C:D:E:F"