Add new settings to save+display multi-algo data

-New settings allow reading of the hash algorithm used to mine a particular block for coins that support this feature and have the algorithm data stored in the raw block data
-An "Algorithm" column has been added to the block page and main transaction homepage when multi-algo data is enabled
-The /ext/getlasttxs api will now return the hash algorithm if reading of the multi-algo data is enabled

scripts/benchmark.js

@@ -66,7 +66,7 @@ mongoose.connect(dbString).then(() => {
                           next_tx();
                         }, timeout);
                       } else {
-                        db.save_tx(txid, block_height, function(err, tx_has_vout) {
+                        db.save_tx(txid, block_height, block, function(err, tx_has_vout) {
                           if (err)
                             console.log(err);
                           else