Extra characters in path or mbtiles names do not load and create extra files on host

[brendan-ward]

On MacOS:

Given a tileset named tileset with extra chars ();?\Å.mbtiles:

• fails to load, complains about missing tiles
• creates a file tileset with extra chars ();? on disk

Expected behavior:

• raise error on opening file if path is not valid for sqlite driver
• do not create any files on disk in case of failure to open path

[brendan-ward]

There are characters that have special meaning for how we open the mbtiles file using the sqlite driver, such as ?. These may be valid paths but break the driver.

Best solution is likely to screen for known special characters and refuse to load these mbtiles files or paths.

/cc @asmyasnikov