Throttle Assist updates for versiuon 4.?

Chris Harlow April 2022

There are a number of additional throttle information commands that have been implemented to assist throttle authors to obtain information from the Command Station in order to implement turnout, route/automation and roster features which are already found in the Withrottle implementations. 
These commands are new and not overlapped with the existing commands which are probabaly due to be obsoleted as they are over complex and unfit for purpose. 

Turnouts:

The conventional turnout definition commands and the ```<H>``` responses do not contain information about the turnout description which may have been provided in an EXRAIL script. A turnout description is much more user friendly than T123 and having a list helps the throttle UI build a suitable set of buttons.

```<JT>``` command returns a list of turnout ids. The throttle should be uninterested in the turnout technology used but needs to know the ids it can throw/close and monitor the current state. 
e.g.  response ```<jT 1 17 22 19>``` 

```<JT 17>`` requests info on turnout 17.
e.g. response ```<jT 17 T "Coal yard exit">``` or ```<jT 17 C "Coal yard exit">```
(T=thrown, C=closed)
or ```<jT 17 C "">``` indicating turnout description not given. 
or ```<jT 17 X>``` indicating turnout unknown (or possibly hidden.) 

Note: It is still the throttles responsibility to monitor the status broadcasts.
 (TBD I'm thinking that the existing broadcast is messy and needs cleaning up)
 However, I'm not keen on dynamically created/deleted turnouts so I have no intention of providing a command that indicates the turnout list has been updated since the throttle started. 
 Also note that turnouts marked in EXRAIL with the HIDDEN keyword instead of a "description" will NOT show up in these commands. 


 Automations/Routes

 A throttle need to know which EXRAIL Automations and Routes it can show the user.

 ```<JA>``` Returns a list of Automations/Routes
 e.g. ```<jA 13 16 23>```
 Indicates route/automation ids.
 Information on each route needs to be obtained by 
 ```<JA 13>``` 
 returns e.g. ```<jA 13 R "description">``` for a route
 or  ```<jA 13 A "description">``` for an automation. 
 or ```<jA 13 X>``` for id not found

 Whats the difference: 
   A Route is just a call to an EXRAIL ROUTE, traditionally to set some turnouts or signals but can be used to perform any kind of EXRAIL function... but its not expecting to know the loco.  
   Thus a route can be triggered by sending in for example ```</START 13>```. 
 
   An Automation is a handoff of the last accessed loco id to an EXRAIL AUTOMATION which would typically drive the loco away.
   Thus an Automation expects a start command with a cab id
   e.g. ```</START 13 3>```


   Roster Information:
   The ```<JR>``` command requests a list of cab ids from the roster.
   e.g. responding ```<jR 3 200 6336>```
   or <jR> for none. 

   Each Roster entry had a name and function map obtained by:
   ```<JR 200>```  reply like ```<jR 200 "Thomas" "whistle/*bell/squeal/panic">
   
   Refer to EXRAIL ROSTER command for function map format.


  Obtaining throttle status.
  ```<t cabid>```  Requests a deliberate update on the cab speed/functions in the same format as the cab broadcast.
     ```<l cabid slot speedbyte functionMap>```
      Note that a slot of -1 indicates that the cab is not in the reminders table and this comand will not reserve a slot until such time as the cab is throttled.


  COMMANDS TO AVOID

  ```<f cab func1 func2>```     Use ```<F cab function 1/0>```
  ```<t  slot cab speed dir>``` Just drop the slot number 
  ```<T commands>``` other than ```<T id 0/1>```
  ```<s>```
  ```<c>```