This introduces new parameters 'map_x_size' and 'map_z_size' that default to 15K
Deprecates 'grid_x_size' and 'grid_z_size'; if they are present, corresponding
values of 'map_x_size' and 'map_z_size' are automatically written in config files.
Also rework compatibility system to better compare versions,
and bump version to 1.0.2-dev1.