4/4 Support GeoTIFF data in TIFF

[don-vip]

This is the fourth and final step towards solving https://github.com/drewnoakes/metadata-extractor/issues/278

It includes:

1. ports of commits from https://github.com/drewnoakes/metadata-extractor-dotnet/pull/307
2. some bug fixes (I'll open a PR in metadata-extractor-dotnet)
3. a new unit test to check GeoTIFF parsing, using data set taken from OSGEO/libgeotiff
4. addition of new EPSG codes used in the libgeotiff samples

It is based on #585. Feel free to close the three others if you prefer to merge all my work in this PR :)