Integrated Helsinki's palvelukartta data to search index.

https://github.com/reitti/reittiopas/issues/158

Hi,

I decided to do something about this. Following pull request adds 10 844 places to the search index. The implementation uses my [pk-extraction script](https://github.com/JaniL/pk-extraction), which is powered by [my wrapper module for palvelukartta's rest api](https://github.com/JaniL/palvelukartta).

pk-extraction needs to be installed globally in order to work with current implementation.

`npm install -g git://github.com/JaniL/pk-extraction.git`