v0.13.0: Alpha release #4

Dinit is very close to being feature-complete.

This is the fourth Alpha release. It contains a number of improvements and new features over the previous release.

NOTE: This release has some minor backwards-incompatible changes. Please read these notes carefully.

This release includes changes contributed by Daniel Kolesa.

Changes:

• A new dinitctl subcommand, "status", can be used to query extended status information for an individual service.
• The default directory for user services has moved to ~/.config/dinit.d (rather than ~/dinit.d).
• Some service settings now expand environment variables (given in the form $VARNAME, in any location that it appears within the setting value). The affected settings are: socket_path, logfile, env_file, working_dir and pid_file.
• The variable substitution in command lines (which remains dependent on the sub-vars load option, for now) uses the same substitution rules and logic as for other settings. In particular, this means that a variable expansion can occur as part of a command line argument (previously it always replaced whole arguments).
• The dinitctl program now uses the value of the DINIT_SOCKET_PATH environment variable, if set, as the default control socket path. (If not set, behaviour is the same as for previous versions).
• A poweroff symlink for shutdown will be installed alongside other symlinks (reboot, halt etc). This allows integration in environments that expect such a command to be available.