#41 esp code for OS X needs fixes

[Jeff Ahrenholz]

- relying on output of logaddr() in hip_esp.c which is not thread safe (identified by D Salizzoni); should use SA2IP to get 32-bit IP instead
- performing memmove() on data path should be replaced by hip_esp_encrypt(..., &data[20], ...) for OS X./home/jeffa/cvs/openhip/hip/src/protocol/hip_main.c