dealing with government shutdown (lack of federally managed web services such as the MMC).  adding a disabled field to Layer model which can be enabled in the admin along with a tooltip/disabled message.  also removing Nautical Charts for now, replacing with Nautical Charts that dont quite reach the southern edge of the region.  These limited Nautical Charts are left out of the application by default and only added to the application when the user hits alt-shift-n (this way they can still be accessed for demoing purposes but wont be seen by everyone viewing the application).
updating gitignore and merging gov-shutdown branch into next-release