Added docs link to InvalidArgument message for preconditions.

- Error messages will appear as: "Invalid Argument: First argument is required, please include address data. Documentation: http://bitcore.io/guide/address.html"

lib/address.js

@@ -58,7 +58,7 @@ function Address(data, network, type) {
     return data;
   }
 
-  $.checkArgument(data, new TypeError('First argument is required, please include address data.'));
+  $.checkArgument(data, 'First argument is required, please include address data.', 'guide/address.html');
 
   if (network && !Networks.get(network)) {
     throw new TypeError('Second argument must be "livenet" or "testnet".');

lib/errors/spec.js

@@ -1,5 +1,7 @@
 'use strict';
 
+var docsURL = 'http://bitcore.io/';
+
 module.exports = [{
   name: 'InvalidB58Char',
   message: 'Invalid Base58 character: {0} in {1}'
@@ -21,7 +23,8 @@ module.exports = [{
 }, {
   name: 'InvalidArgument',
   message: function() {
-    return 'Invalid Argument' + (arguments[0] ? (': ' + arguments[0]) : '');
+    return 'Invalid Argument' + (arguments[0] ? (': ' + arguments[0]) : '') +
+      (arguments[1] ? (' Documentation: ' + docsURL + arguments[1]): '');
   }
 }, {
   name: 'AbstractMethodInvoked',

lib/util/preconditions.js

@@ -9,9 +9,9 @@ module.exports = {
       throw new errors.InvalidState(message);
     }
   },
-  checkArgument: function(condition, argumentName, message) {
+  checkArgument: function(condition, argumentName, message, docsPath) {
     if (!condition) {
-      throw new errors.InvalidArgument(argumentName, message);
+      throw new errors.InvalidArgument(argumentName, message, docsPath);
     }
   },
   checkArgumentType: function(argument, type, argumentName) {