constants separated to const.js file

lib/const.js

@@ -0,0 +1,33 @@
+/*
+    This file is part of ethereum.js.
+
+    ethereum.js is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ethereum.js is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with ethereum.js.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/** @file const.js
+ * @authors:
+ *   Marek Kotewicz <marek@ethdev.com>
+ * @date 2015
+ */
+
+/// required to define ETH_BIGNUMBER_ROUNDING_MODE
+if (process.env.NODE_ENV !== 'build') {
+    var BigNumber = require('bignumber.js'); // jshint ignore:line
+}
+
+module.exports = {
+    ETH_PADDING: 32,
+    ETH_METHOD_SIGNATURE_LENGTH: 4,
+    ETH_BIGNUMBER_ROUNDING_MODE: { ROUNDING_MODE: BigNumber.ROUND_DOWN }
+};
+