Added water.php page

water.php page demonstrates interactions between water-related GIS
layers and the interactive map, including a list that filters based on
map view, buttons to add layers to map, legend and links.
Improved look & performance of TOC list

Added collapsible accordions with tabbed legend & metadata.
Added to water.php

Added ALSC and changed FEMA NFHL layer
Merge remote-tracking branch 'origin/master'