Django WMS Browser

Context: In the interest of improving compatibility with existing infrastructure, GeoNode should allow "adding" or "subscribing" to a 3rd-party WMS service and providing a browser-accessible and human-readable presentation of the layers presented.  As a first step toward that goal, is to create a standalone app/service to translate WMS Capabilities to HTML.

Details:
Configuration: An administrator should need only to provide the URL to a WMS service or Capabilities document and allow the rest to be inferred from data available via OGC web services.

Presentation: 

* The index page for the site will be a listing of all known layers, with appropriate navigation aids.
* Clicking on a layer link from the index page brings up a 'detail' page for the layer, presenting the layer's title and other metadata, as well as an interactive ('slippy') map to allow browsing through the contents of each layer.
* For non-raster layers, users should also be able to explore the attribute data associated with the geometries in a table. 
* Each layer should include instructions (code templates etc.) for integrating the layer into other services such as OpenLayers maps.

Prerequisites:

* GeoDjango http://code.djangoproject.com/wiki/GeoDjango
* Spatial Database (tested with PostgreSQL + PostGIS, assumed, but not tested, to work with MySQL and Oracle Spatial)
* OWSLib http://trac.gispython.org/lab/wiki/OwsLib (using forked version wiht improvements here https://github.com/ortelius/OWSLib)
* BeautifulSoup http://www.crummy.com/software/BeautifulSoup/
* olwidget http://github.com/yourcelf/olwidget

General TODO: (in Priority Order)
	Implement Basic Doctests Tests for Model Functions
	Implement Unit Tests for Model Functions
		-WmsEndpoint.parse_save_wms_url
		WmsEndpoint.parse_save_output_formats
		WmsEndpoint.parse_save_capabilities
		WmsEndpoint.parse_save_wms_layers
		WmsLayer.generate_preview_image
		WmsLayer.parse_save_styles
		WmsLayer.generate_preview_image
		WmsLayer.retrieve_layer_attributes
		WmsLayer.valid_latlon_bbox
		WmsLayer.parse_save_layer_attribution
		WmsLayer.parse_save_style
	-Implement index view in wmsb.views
	-Implement index template
		-List all exiting layers -> Link to WmsLayer info view
		-Navigation/Paging
		Form to add new endpoint/server (single form field for url)
	-Implement Endpoint/Server listing view in wmsb.views
	-Implement Endpont/Server listing template
		-List of all exisitng Endpoint/Servers -> Link to WmsEndpoint info view
		-Navigation/Paging
		Form to add new endpoint/server (single form field for url)
	-Implement WmsEndpoint info/detail view in wmsb.views
		-List all layers for Endpoint/Server
		OL Map with footprints for each layer?
	-Implement WmsLayer info/detail view in wmsb.views
	-Implement WmsLayer template
		List all layer metadata
		-List Layer Attributes (if available) in table.
		-OL Map with WMS Layer
		Code Templaes for embedding
			OpenLayers
			Google Maps
			Google Earth/KML?
	Implement Endpoint/Server/Layer search
		Keyword/Full Text
		By BBOX
	Customize Admin for WmsLayer to include WMS in OL Map
	Modify olwidget to work in 4326 (several tested WMS Servers do not support 900913)