62defaultkeyword

This is the updated version of the previous pull request (bug fixes and enhancements)

![vpt](https://cloud.githubusercontent.com/assets/2107541/3886850/9c85d3ea-21e5-11e4-95da-321e2269f9ba.jpg)
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In the above example (`/shop/%postname%/vv`), the default keyword will be trigger whenever the user accesses a virtual page with no keywords e.g. `/shop/vv` .
This bug has been removed.