Removed unused imports.
Add HAS_SPATIAL_DB checkout to gis.test.utils.
Made distapp tests skip if requirements aren't met.
Made geo3d tests skip if requirements aren't met.
Made geoadmin tests skip if requirements aren't met.
Made geoapp tests skip if requirements aren't met.
Made geogapp tests skip if requirements aren't met.
Made inspectapp tests skip if requirements aren't met.
Made layermap tests skip if requirements aren't met.
Made relatedapp tests skip if requirements aren't met.