[maps.soton] Quick Note on Tileservers

[Christopher Baines]

I have just set up a tileserver using tilelite (rather than
mod_tile/renderd) which appears to work well. This is currently backing
the tiles on [1].

Tilelite [2] appears to be slightly simpler than mod_tile, and most
importantly, available in Debian.

1: http://cbaines.net/soton/
2: https://github.com/springmeyer/tilelite
3: https://tracker.debian.org/pkg/tilelite