Variable max_cells in st_buffer

[olegzhelezn]

I am buffering a series of polygons of different size using S2 (I have a large area so projecting them into one CS is not a good option). It provides correct estimates, however, the quality of the buffers is variable for large and small polygons. I suggest that the variable max_cells could be set up using a list of values (e.g. proportional to the perimeter of the polygon). Right now it is constant for all polygons.