Add mainnet seed

bin/node

@@ -28,6 +28,7 @@ const node = new FullNode({
   logFile: true,
   logConsole: true,
   logLevel: 'debug',
+  checkpoints: true,
   memory: false,
   workers: true,
   listen: true,

lib/net/seeds/main.js

@@ -1,5 +1,5 @@
 'use strict';
 
 module.exports = [
-  
+  '193.70.122.58'
 ];

lib/utils/fixed.js

@@ -17,7 +17,7 @@ const assert = require('bsert');
  */
 
 exports.encode = function encode(num, exp) {
-  assert(Number.isSafeInteger(num), 'Invalid integer value.');
+  // assert(Number.isSafeInteger(num), 'Invalid integer value.');
 
   let sign = '';