Regtest

[lvaccaro]

Add support to RegTest network.

• Preprocessor macro BITCOIN_REGTEST: to discriminate regtest code.
• Add BITCOIN_REGTEST=1 in "Preprocessor macro" in order to compile.
• Define your own dns_seeds in BRPeerManager.c.
• Define your port STANDARD_PORT in BRPeer.h
• Add regtest macro:

#define BITCOIN_PUBKEY_ADDRESS_REGTEST 111
#define BITCOIN_SCRIPT_ADDRESS_REGTEST 196
#define BITCOIN_PRIVKEY_REGTEST        239
#define BIP32_XPRV     "\x04\x35\x83\x94"
#define BIP32_XPUB     "\x04\x35\x87\xCF"
#define MAX_PROOF_OF_WORK 0x207fffff
#define MAGIC_NUMBER 0xdab5bffa
#define STANDARD_PORT 18444

static const struct { uint32_t height; const char *hash; uint32_t timestamp; uint32_t target; } checkpoint_array[] = {
    {      0, "0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206", 1296688602, 0x207fffff }
    };

static const char *dns_seeds[] = {
    "example.com"
   };

[voisine]

Hi @lvaccaro, I've refactored brpeermanager to now accept a chainparams argument. Do you think you could update your PR to use it? It should make it simpler.