release: v0.4.0

appc spec version: v0.8.4

This minor release largely exists to bump the version of the AppC spec the
acbuild is using.

- Bumps the version of the AppC spec to v0.8.4.
- Adds the ability for acbuild to generate man pages for itself.

appc spec version: v0.7.1+git

v0.2.2 is a minor release incorporating a handful of changes since v0.2.1.
Things this release includes:

- Don't require a starting character of `.` or `/` when specifying an image for
  the `--modify` flag.
- Adds support for specifying a local directory with `begin`, for use as the
  initial rootfs of the ACI.
- Adds support for the `run` command on systems with a version of systemd <
  209.
- Versions of dependencies can be specified using tag syntax.
- A bug related to the handling of hard links in tars was found, and fixed.
- A history of acbuild commands performed is now tracked in annotations in the
  ACI being worked on. This can be disabled via a flag.

v0.2.1

appc spec version: v0.7.1+git5a7af19

v0.2.0 changed the default behavior of the copy command, requiring that the
user passed the `-T` flag to use the previous default behavior. This release
flips that, such that the default will be as it was before, and a new flag must
be passed to use the new behavior.

v0.2.0

appc spec version: v0.7.1+git5a7af19

- Automatically fills in the `os` and `arch` labels on new builds.
- The `--modify` flag failed to properly use an alternate work context.
- The help page has been reformatted.
- Extracting ACIs during begin no longer requires root.
- Modifying an existing ACI that didn't have the `app` field set would cause an
  error.
- Copy now has two modes of operation, toggled with the `-T` flag. The new mode
  allows copying many files at once into the ACI, as opposed to a single one.
- When using begin with a local file, the path must now start with a `.`, `~`,
  or `/`.

The following commands have been added to acbuild since the last release:
- cat-manifest
- isolator add
- isolator remove
- replace-manifest
- set-event-handler pre-start
- set-event-handler post-stop
- set-working-directory

appc spec version: v0.7.1+git5a7af19

v0.1.1 has a couple of bug fixes since the initial release:

- When the `--debug` flag was combined with the `run` command acbuild would
  panic. (containers#56)
- When a remote ACI was specified with `begin`, acbuild would emit an error and
  exit after downloading the ACI. (containers#58)

Initial release