webpack: split sqlite3-binding.js out so that it could be override by webpack … (#1268)

* Split sqlite3-binding.js out so that it could be override by webpack options.

Co-authored-by: Kewde <kewde@particl.io>

lib/sqlite3-binding.js

+var binary = require('node-pre-gyp');
+var path = require('path');
+var binding_path = binary.find(path.resolve(path.join(__dirname,'../package.json')));
+var binding = require(binding_path);
+module.exports = exports = binding;

lib/sqlite3.js

-var binary = require('node-pre-gyp');
 var path = require('path');
-var binding_path = binary.find(path.resolve(path.join(__dirname,'../package.json')));
-var binding = require(binding_path);
-var sqlite3 = module.exports = exports = binding;
+var sqlite3 = require('./sqlite3-binding.js');
 var EventEmitter = require('events').EventEmitter;
+module.exports = exports = sqlite3;
 
 function normalizeMethod (fn) {
     return function (sql) {