Liko-12: xshell (advanced shell)

New Features

• What feature(s) did you add?
• I have added a more advanced shell to the fantasy console, that allows the user to chain commands.
  It currently allows for running the new shell in a non-interactive mode.
• Currently, it allows for the chaining of commands conditionally (&) or unconditionally (;).
• In conditional chaining the next command only runs if the last command exited successfully, and in unconditional chaining, the next command runs no matter what happened with the last.

• How did you implement it/them?
• I modified the general terminal code, to return the result of ran commands, allowing conditional chaining of commands.
• At first, it used code in the xshell program for parsing. Now, however, it organizes the code better through use of the built-in language parser to parse the input, and interpret it as a chain of commands separated by characters.
• This edit contains two new files, one contains the new language for the parsing system, and the other contains the main program for xhsell.
• The existing programs still need to be modified to return their error status, to further improve xshell's conditional chaining.
• A lot of the code that was used was already used in parts of LIKO-12