support for wms-c / geowebcache

Some syntax fixes so that GeoWebCache will work with NM in direct integration mode and as WMS-C.  This partially addresses #473.

WMTS and TMS require additional ViewModels or extensions to the WebMapService view models.
I believe it is they may fail.  I haven't found any that actually do.  And once we dump the init_nm.json file, which will hopefully be soon, we won't have that to check.  The better way is probably to build out getCapabilities so that it actually checks rather then having to pre-configure, but we don't do that by default until we move to the ckan front end which is next up.