refactor(commands): commands now store all info about themselves

Makes it easier to modify a command

Each command exports an object:
{
  directive: string or array of commands that call this handler
  handler: function to process the command
  syntax: string of how to call the command
  description: human readable explaination of command
  flags: optional object of flags
}

src/commands/registration/cdup.js

@@ -0,0 +1,11 @@
+const cwd = require('./cwd').handler;
+
+module.exports = {
+  directive: ['CDUP', 'XCUP'],
+  handler: function(args) {
+    args.command._ = [args.command._[0], '..'];
+    return cwd.call(this, args);
+  },
+  syntax: '{{cmd}}',
+  description: 'Change to Parent Directory'
+}