How to use editor commands

 The editor responds to a large set of editor commands. These commands
 perform tasks from moving the cursor, to copying blocks. Each command has
 a name and possibly a list of arguments that go with it. For example, the
 line_insert command needs to be supplied with the text for the new line but
 the character_left command simply moves the cursor left one space.

 When any of the the 'non-special' keys (alphanumerics etc.) are pressed, the
 editor internally creates a character_type X command and executes it.

 Any command can be executed by pressing escape and selecting the command
 from the 2 tier menu system.

 eg:  user presses Esc                   top level menu is brought up.
      user selects line                  line menu is brought up.
      user selects insert                user has effectively selected
                                         line_insert at this point, and now
                                         line_insert prompts for the line.
      user types Hello                   Hello is inserted as a new line.

 At any point the user can press Esc to abort the process.

 Alternatively the command and its arguments can be typed in directly if the
 user selects COMMAND from the main menu. This is awkward since the user
 does need to know exactly what arguments are expected and what the correct
 spelling of the command required is.

 eg:  user presses Esc                   top level menu is brought up.
      user selects COMMAND               editor prompts for command.
      user types line_insert "Hello"     Hello is inserted as a new line.

 Also, when AE loads up, the first thing it does is read the initialisation
 file. It finds this by taking the full path of where it was loaded from and
 replacing the .EXE with .INI. eg: if C:\AE\AE.EXE was loaded, the file
 C:\AE\AE.INI will be used to initialise with.

 Each line not starting with a ; is executed in this way. This is used set
 up the initial key-bindings and language configurations.

 The arguments can be of the types below :-

      <number>       The command expects a non-negative number.
                     eg: a line number or repeat count such as 5.

      <string>       The command expects a string.
                     eg: a filename or search pattern such as "grep.c".

      <character>    The command expects a character.
                     The ASCII code can be supplied instead if the menu
                     system is not being used.
                     eg: a character to insert such as 'A' or 65.

      <yes/no>       The command expects confirmation.
                     eg: confirmation of choice or direction is forwards?

      <never/if_open/always>
                     This specifies when to enter folds. Never, if they are
                     open folds, or always.

 Quite often when a string argument is required, it is known in advance what
 the allowable replys are. So if you are supplying arguments interactively a
 menu will be given of allowable replys. An example of this is when you use
 the buffer_write command. The only allowable arguments are the names of the
 buffers, so these are supplied in a menu, rather than having the user type
 in the name.

 If when not using the menu system to select commands you supply ? as an
 argument, you will be prompted for the argument interactively.

 eg:  line_insert "Hello"                Inserts Hello.
      line_insert ?                      Prompts the user for a string
                                         and then inserts it.

 If you use the argment . as the argument that is intended to be a
 buffer name or language name, the current setting of buffer name or
 language name is used.

 eg:  buffer_write .                     Writes current buffer to disk.