Performance, bug fixes, and style improvements

We've been using this branch of nodetiles-core in localdata-tiles for a long time. It's time to move it to master (and eventually get a PR to the nodetiles project). This PR includes months of major & minor improvements:

* Performance improvements!
* Cleans up some excess logs and other unused files
* Updates some dependencies 
* Improved comments in rendering
* Minor style tweaks