If an argument is not understood as subcommand, but has a
high-confidence match in the list of all known subcommands, we will use
this one to print a customized error message.
Previously, it would say that a positional argument wasn't understood,
now it will say that a subcommand was unknown, and if the user meant
`high-confidence-candidate`.
If the argument doesn't sufficiently match any subcommand, the default
handling will take over and try to treat it as positional argument.
* added dependency to `strsym` crate
* new `did_you_mean` function uses `strsim::jaro_winkler(...)` to look
for good candidates.
Related to #103
* assure `make test` works on OSX as well
* simplified entire makefile, by basically removing sed invocations to
manipulate the Cargo.toml file under source control.
* *works for me* predicate
This should probably be tested on another system as well, just to be
sure it makes sense for everyone.
