Hardening/libcurl

**DON'T MERGE**

Orion uses libcurl to send HTTP requests.
I understand that this is the malloc() to initialize the httpResponse->memory. Although the variable can grow automatically, maybe it would be more efficient to use an initial allocation greater than 1 byte (to save a first reallocation operation). My suggestion would be to have a LIBCURL_MEMORY_INITIAL_MEMORY define (or a more appropiate and shorter alternative) and set it with a reasonable value.

Or maybe I'm not understanding correctly how this works and this comment could be ignored :)