Fix for link function creating incorrectly nested URL parameters

This is a small fix for issue #24
(https://github.com/yiiext/smarty-renderer/issues/24).

>The current link function is creating URLs with parameters incorrectly
nested. This leads to URLs that look like:
`controller/action/0%5Bparam%5D/value` when encoded, and
`registration/controller/action/0[param]/value` when decoded.
Merge pull request #25 from ciarand/master

Fix for link function creating incorrectly nested URL parameters (#24)