Updated the ObservatoryMetadata and Observatory.py files to point to the...

Updated the ObservatoryMetadata and Observatory.py files to point to the default_metadata dictionary only. Also edited the declination_base argument so that it defualts to an int = None rather than 0. This change is reflected in the default_metadata as well. Anywhere declination_base didn't exists or equaled 0 is now set to 'declination_base' = None