By default ensure external_ai tool call related special chat session
starts with tool calls disabled and client side sliding window of 1.
Add a helper in SimpleChat class to set these along with clearing of
any chat history.
Inturn now give the user flexibility to change this from within
the program, if they need to for what ever reason, till the program
restarts.
Gives quick overview of the features, given that the original readme
(now docs/details.md++) got created over a period of disjoined time
as features got added.
hanishkvc