Only load spec files once

- Fixes #161

Author: Gregg Van Hove

lib/jasmine.js

@@ -86,7 +86,6 @@ Jasmine.prototype.addMatchers = function(matchers) {
 
 Jasmine.prototype.loadSpecs = function() {
   this.specFiles.forEach(function(file) {
-    delete require.cache[require.resolve(file)];
     require(file);
   });
 };