Pueue

Fixed
- Prevent a daemon crash, if the client dies while daemon receives data.

Fixed
- Fix default shell set function

Added
- Allow to set a custom shell instead of `/bin/sh`.
This is done by callingthe `pueue config customShell`. Use `default` for `/bin/sh`.
By setting a custom shell it's possible to use aliases or environment variables.
Be careful! This probably causes some bugs, as every shell behaves differently.

Changed
- The `kill` command has been remodeled. Instead of always sending an `SigKill` it now allows you to specify the signal that should be sent (default is `SIGTERM`).
By default the signal will be sent to the processes spawned by the `shell` parent process. The new `-a/--all` flag is provided in case you want to send the signal to the parent process as well.
Available signals can be viewed with `pueue kill -h` under the `-s` flag. Either the int `15` the full name `sigterm/SIGTERM` or the abbreviation `term/TERM` can be used.
For now we support: SIGHUP, SIGINT, SIGQUIT, SIGKILL, SIGTERM, SIGCONT, SIGSTOP
- The `stop` command has been removed, as it is now covered by the `kill` command

Fixed
- Fixed missing return message for `send`.
- Write queue more often. This prevents entries from disappearing after reboot.
- Set `paused` entries to `queued` on restart.

Added
- Allow switching of `stashed` entries in queue.

Changed
- `remove`, `restart`, `stash`, `enqueue` commands can receive multiple keys instead of a single key.
- `log`, `pause`, `start`, `kill`, `stop` commands don't have a `--key` parameter anymore. They can now receive a list of keys without providing a flag i.e. `pueue start 0 1` instead of `pueue start -k 0 && pueue start -k 1`. The default behavior if no key is provided stays the same for all commands.
- Daemon API now requires a `keys` parameter where `type(keys) == list` for the commands listed above.

Fixed
- Fixed daemon crash when restarting a non-existing entry.
- Fixed client crash for empty queue with `show`.
- Fixed client crash for invalid key with `show`.
- Wrong daemon response for `kill` command.
- `stop` or `kill` sends the signal to all processes spawned by the shell process. This bug affected all command strings which caused the subprocess to spawn a `/bin/sh -c {command}` process.
- `pause` or `start` sends the signal to all processes spawned by the shell process. This bug affected all command strings which caused the subprocess to spawn a `/bin/sh -c {command}` process.