Merge postgis branch into master.

The "charts" directory of this postgis branch has a working example of a basic chart pulling data from the PostGIS database using a Node.js script for the API. The same Node.js script also serves static HighCharts HTML/JavaScript files to avoid the cross-site (cross-domain) scripting issue that arises if we try to use Node.js with Apache. After this merge, I'll work on integrating all of this into the OpenLayers app.