[FEATURE] Allow see project build status in cctray xml format

Contribution Type: new feature
Primary Area: front-end
Link to Intent to Implement:  *PHPCI_URL*/build-status/ccxml/*ProjectId*

Description of change: 
If project have public access to build status, it will also allow generate build status in ccmenu xml format.
Will be shown project stats by all submitted branches.

Expected result
```
<Projects>
<Project name="Project / develop" activity="Building" lastBuildLabel="23" lastBuildStatus="Failure" lastBuildTime="2014-12-14T17:41:05+0200" webUrl="http://phpci.dev/build/view/23"/>
<Project name="Project / master" activity="Sleeping" lastBuildLabel="6" lastBuildStatus="Success" lastBuildTime="2014-12-14T15:38:34+0200" webUrl="http://phpci.dev/build/view/6"/>
</Projects>
```

Use CCMenu on Mac, CCTray on Windows, JCCTray on Windows or Linux, or CCMonitor for Firefox.

    $this->response->setHeader('Content-Type', 'text/xml');
    $this->response->setContent($xml->asXML());
    $this->response->flush();