Package libshell: Information

- shell-args:
  + Properly handle an argument starting with a dash.

- shell-unittest changes:
  + Add option to hide successful tests
- shell-run changes:
  + Improve compatibility with mksh
- shell-cmdline changes:
  + Add another argument to cmdline_foreach()
    to indicate the difference between a flag and a parameter with an argument
- shell-git-config changes:
  + Add git_config_foreach to list values for env parser
- Other changes:
  + Add Travis CI
  + Add compatibility with ksh
  + Run tests with few shells
  + Enforce documentation of all public functions
  + Add verification by shellcheck
  + Use scdoc instead of md2man

- Other changes:
  + shell-temp: Add docs
  + shell-git-config: Add functions to store values in memory
  + shell-temp: Turn off verbose