adding pansharpening guide @hrwgc
adding complex 3d structures guide @hrwgc
Merge branch 'satellite-docs' of github.com:mapbox/tilemill into satellite-docs
copy modifications to make these guides not blog posts
pansharpening process not solid enough for guide
Merge pull request #2019 from mapbox/satellite-docs

nuked pansharpening post. revisit when we have a more solid process.