0.4.0

This is the third alpha release of the shell. It brings again a lot of new features and bugs. :) Below are changes since the last version:

Tag BREAKING means the change break compatibility with a previous version
of the shell.

Added

• BREAKING: Version to the plugins API
• Information about supported API version by plugin to plugin show command
• Information about used API calls by plugin to plugin show command
• Deleting a character with Backspace key in the middle of the user's input
• Canceling entering the command with Ctrl-c
• Showing error message when a plugin sends unknown request or response to the
  shell
• Ability to add, remove or replace the shell's commands with the shell's
  plugins
• Ability to add, remove or update the shell's help's entries with the shell's
  plugins

Changed

• Updated README.md
• Updated contributing guide
• BREAKING: Better, more effective system of plugins
• Better help entry for list of subcommands for the selected command
• BREAKING: Better, more advanced system of help

Fixed

• Typos in README.md
• Crash when trying to enter a directory outside the user's home directory tree
• Executing aliases which arguments contain whitespaces
• Backspace key during editing a command entered by the user