Chores (mostly documentation)

[rouson]

To Do

In the root-directory README.md file,

• Add a comprehensive list of the supported string_t() constructor functions and actual argument types:
  • complex
  • double precision
  • double precision complex
  • integer
  • logical
  • real
• Add a demonstration of the array_of_strings function that produces an array of the separated values from a string containing a separated-value list.
• Decide whether to add the following functions that are public but are provided automatically if users start by copying the demonstration test suite:
  • command_line_t
  • github_ci
• Decide whether to add user_defined_collectives_m to the julienne_m public interface and document it in the README.md. Currently, it is only used internally to Julienne, but could be useful to users.

Additional chore:

• Decide whether to move julienne_bin_m to the Sourcery repository because it is not used anywhere in Julienne.