Many import errors from modules being renamed (e.g. GEO -> geo), but imports not using the new name

[chriskilding]

When running Ortho4XP from the dev branch (latest commit), the first phases of building a tile succeed (Assemble vector data, Triangulate 3D Mesh, Draw water masks), but the Build Imagery/DSF phase fails due to import errors...

The problem seems to be that lots of modules were renamed, but when functions from these modules are imported, some of the imports still use the old name of the module. This cannot resolve, so an import error arises.

(For example, dsf.py uses GEO.wgs84_to_orthogrid, but since the module was renamed to geo, the code needs to use geo.wgs84_to_orthogrid instead.)