Create cargo template as used in the book

[killercup]

The book currently refers to a template you can get with cargo-generate to start writing your CLI crate.

This template repo doesn't exist! We should crate one.

Feel free to be inspired by quicli.

[killercup]

@Keats has a pretty neat template (for kickstart) here: https://github.com/Keats/rust-cli-template

[Dylan-DPC-zz]

Created an initial template here

We need to discuss which features should go into the template.

[yoshuawuyts]

Here's example output generated by my own CLI generator (example, template, generator). Some notable features include:

• exitfailure integration for a series of error causes to be shown.
• human-panic integration
• colored CLI output through structopt
• logger + log levels enabled by default
• autocompletion
• structured error definitions for the lib portion of the app

Some things I wish were better:

• man page generation (hopefully soon)
• exitfailure doesn't use the log crate, which means logs can be inconsistent.
• human-panic does not show the error that caused the crash, which is not ideal during development.
• all dependencies for the lib portion of the crate must also be build dependencies. This almost feels like a bug, but I haven't been able to figure out how to solve it.