fixed #28 and other small node.js issues

lib/abi.js

@@ -23,10 +23,10 @@
 
 // TODO: is these line is supposed to be here? 
 if (process.env.NODE_ENV !== 'build') {
-    var web3 = require('./web3'); // jshint ignore:line
+    var BigNumber = require('bignumber.js'); // jshint ignore:line
 }
 
-var BigNumber = require('bignumber.js');
+var web3 = require('./web3'); // jshint ignore:line
 
 // TODO: make these be actually accurate instead of falling back onto JS's doubles.
 var hexToDec = function (hex) {