Add Globe.baseColor

Allows for setting the color of the globe when no imagery is available.
Minor Sandcastle fixes
Merge pull request #2151 from AnalyticalGraphicsInc/fixes

Minor Sandcastle fixes
Changes after review

1. Add unit tests for changing base color.
2. Make sure new properties are initialized in the constructor.
Merge pull request #2149 from AnalyticalGraphicsInc/globe-color

Add Globe.baseColor
Minor tweaks to Geocoder

This prevents the Geocoder widget from both allowing editing of text while searching and also prevents submitting of the text "Searching..." while already geocoding.

Fixes #2087
Merge pull request #2153 from AnalyticalGraphicsInc/geocoder-searching

Minor tweaks to Geocoder