Option to skip and report, or improved logging of failed tiles.

Nobody has claimed this yet.

👋 When running `tilelive-copy --scheme=list --list=/list_of_tiles.txt` I occasionally see the following error, which stops tilelive-copy from any further processing of the `list_of_tiles.txt` list :

```
if (err) throw err;
^

TypeError: required parameters (z, x, and y) must be greater then or equal to zero
at TypeError (native)
at Function.Bridge.getVector (/usr/local/lib/node_modules/tilelive-bridge/index.js:243:21)
at /usr/local/lib/node_modules/tilelive-bridge/index.js:185:20
at dispense (/usr/local/lib/node_modules/tilelive-bridge/node_modules/generic-pool/lib/generic-pool.js:258:16)
at Object.me.release (/usr/local/lib/node_modules/tilelive-bridge/node_modules/generic-pool/lib/generic-pool.js:368:5)
at /usr/local/lib/node_modules/tilelive-bridge/index.js:282:21
```

I've inspected my tiles list a number of ways and I can't determine the problematic tile, so it would be helpful to have a `--skip-failed-tiles` flag, or similar, which would simply move on to the next tile (while outputting the failed tile info) and/or a `--debug` / `--verbose` flag to print out the current tile that's being processed, so it's easier to debug when this case occurs.

I can work on a PR for either/both, would love opinions on whether this approach would be sensible/helpful.

Thanks!

Start at the tilelive-copy command with --scheme=list and inspect how it processes each tile from --list and reports errors. Reproduce the failure with a tile list, then clarify whether the intended result is identifying failed tiles, skipping them, or both; done means the chosen behavior is observable and processing matches that decision.

Written by the indexing model from the issue text.