v2.4.0

• New cli_memo() function to create a list of items or tasks.

• New cli::cli() function to create a single cli message from multiple
  cli calls (#170).

• cli now highlights weird names, e.g. path names with leading or
  trailing space (#227).

• Styling is fixed at several places. In particular, nested lists should
  be now formatted better (#221).

• New spark_bar() and spark_line() funcions to draw small bar or
  line charts.