Introducing `pageURI` method to handle test cases links with custom location.

Basically this should solve issues like #177.
Developer should be able to customize `pageURI` method for the reporter he's using.
Ex.:

```javascript
var jasmineEnv = jasmine.getEnv();
var reporter = new jasmine.TrivialReporter();
reporter.pageURI = function(path){ return window.location.pathname + path };
jasmineEnv.addReporter(reporter);
jasmineEnv.execute();
```

```javascript
jasmine.HtmlReporter.SpecView.prototype.pageURI = function(path){ return window.location.pathname + path };
var jasmineEnv = jasmine.getEnv();
var reporter = new jasmine.HtmlReporter();
jasmineEnv.addReporter(reporter);
jasmineEnv.execute();
```