Feature/final data
Adds a function tilegrid to the TileGrid class. tilegrid takes all data that's been calculated up to now (the multiresolution-grid from quadtree_grid and the coast-tile related geometries from vector_buffer) and compiles a fully classified GeoDataFrame of tiles, land and water geometries and area values in UTM and AEA. The GeoDataFrame can later be used for export to file or for import to the tile-database.
