Change pre-quantization defaults.

Pre-quantization is now disabled by default if only a single input is provided, since the assumption is that when there’s only a single input, it is likely to be consistent and thus we do not need fuzzy-matching to determine shared arcs.

Also, the -q command line option now only sets post-quantization, requiring you to set pre-quantization explicitly if necessary.
i.e. add the equivalent to `alias: "q"` to the "q1" option (or vice versa).  I assume optimist allows multiple aliases.