Remove failure entirely

Migrate pond away from failure

Just use an option, this is not used anyway.

Convert dbus code and brightclt to anyhow

More migrating away from failure.  Use anyhow for the binary.

Create specific error type for BacklightDevice

This migrates away from failure for the core BacklightDevice type.

Modern doc comments

Clippy

More sane matching

Stop using extern crate

Rely on the simpler path management in the 2018 edition and newer
features for macros in rust stable for these as well.

Use dyn Trait syntax

The plain Trait syntax is no longer recommended as this is
clearer.

Update README for sourcehat

Since Bitbucket is turning down mercurial support we needed to move
this repo.  Let's try out sourcehat.

Added tag 3.0.0 for changeset 5cbcc9890216

Update cargo.lock for new version number

Forgot this in the last commit

Bump the version

Package using cargo-deb

Using cargo-deb now produces a reasonably decent package.  It installs
command line completions, the binaries, udev rules, D-Bus
configuration and the systemd system service, leaving the service started.

Update dependencies

Add missing license file

Oops.

Add wait_timeout() method

Not sure I'll end up using this though.

Allow controlling step and minimum value in acpi mode

Also remove the acpi module, it belonged in the binary source code
really since it was using failure::Error.

Remove this temp binary again

Refactor brightctl to use bright::dbus::Client

Now that we have this client, we should use it whereever we need a client.