cleaner should interface export.

- also aliased `chai.Should()` as the original would be overwritten after the first call (helps when using watch mode for test runners)

lib/interface/should.js

@@ -7,19 +7,19 @@
 module.exports = function (chai, util) {
   var Assertion = chai.Assertion;
 
-  chai.should = function () {
+  function loadShould () {
     // modify Object.prototype to have `should`
-    Object.defineProperty(Object.prototype, 'should', {
-      set: function(){},
-      get: function(){
-        if (this instanceof String || this instanceof Number) {
-          return new Assertion(this.constructor(this));
-        } else if (this instanceof Boolean) {
-          return new Assertion(this == true);
+    Object.defineProperty(Object.prototype, 'should',
+      { set: function () {}
+      , get: function(){
+          if (this instanceof String || this instanceof Number) {
+            return new Assertion(this.constructor(this));
+          } else if (this instanceof Boolean) {
+            return new Assertion(this == true);
+          }
+          return new Assertion(this);
         }
-        return new Assertion(this);
-      },
-      configurable: true
+      , configurable: true
     });
 
     var should = {};
@@ -56,4 +56,7 @@ module.exports = function (chai, util) {
 
     return should;
   };
+
+  chai.should = loadShould;
+  chai.Should = loadShould;
 };

test/should.js

@@ -7,14 +7,14 @@ if (!chai) {
   var chai = require('..');
 }
 
-var should = chai.should();
+var should = chai.Should();
 
 function err(fn, msg) {
   try {
     fn();
     throw new chai.AssertionError({ message: 'Expected an error' });
   } catch (err) {
-    should.equal(err.message, msg);
+    chai.expect(err.message).to.equal(msg);
   }
 }