Merge pull request monero-project#12 from stoffu/mainnet-v7-fork

Set mainnet v7 fork height to 963500 (June 3rd 2018) with diff reset to 2 billion

src/cryptonote_core/blockchain.cpp

@@ -92,8 +92,12 @@ static const struct {
 } mainnet_hard_forks[] = {
   // version 1 from the start of the blockchain
   { 1, 1, 0, 1341378000, 0 },
+
+  // versions 2, 3, 4, 5 and 6 are skipped, in favor of reducing the cost of adopting the POW change and other consensus updates from Monero
+  // version 7 starts from block 963500, which is on or around the 3rd of June, 2018. Fork time finalised on 2018-05-24.
+  { 7, 963500, 0, 1527137212, 2000000000 },
 };
-static const uint64_t mainnet_hard_fork_version_1_till = 0;
+static const uint64_t mainnet_hard_fork_version_1_till = 963499;
 
 static const struct {
   uint8_t version;