Presto functions for geospatial hexagons

Copy jars to presto plugin folder and enjoy some useful gojuno hexgrid functions

Examples:

select hex_code(32.4,28.5, 512.0);
25202343

select hex_neighbors(25202343,512.0);
{25202342,25202348,25202341,25202349,25202352,25202354}

select hex_cover('POLYGON((34.767608642578125 32.0710836150551, 34.78889465332031 32.0710836150551, 34.78889465332031 32.08635607345998, 34.767608642578125 32.08635607345998, 34.767608642578125 32.0710836150551))')
{19784831,19784917,19784919,19785000,19785002,19785088,19785001,19785003,19785089,19784998,19785004,19785006,19784999,19785005,19785007}