Add a flowchart for the interpreter.

Using PlantUML.

README.md

@@ -135,6 +135,9 @@ available functions of the Joy system.  Together the stack, expression, and dict
 are the entire state of the Joy interpreter.
 
 
+![joy_interpreter_flowchart.svg](/joy_interpreter_flowchart.svg)
+
+
 ### Stack / Quote / List / Sequence
 
 When talking about Joy we use the terms "stack", "quote", "sequence",

docs/_joy_interpreter_flowchart_url.txt

@@ -0,0 +1 @@
+//www.plantuml.com/plantuml/png/NP0xRiCm38PtdO905sTe3Y0FpIMApafCruGbqg3e9hvz6Jj2WIuIXVy1yRjKIsfhoM4VGhXFb14wV2oAjP8mK3sVpoU_e6FXTooBRQS04B_HWF5XOAW5HfK2Vx7U7JH2zzHQXKt8qDMjN2K_6mx7yGPY6EXc7aswVJGpos44U5CSeYQg29yyizpvItJeN-fLCStxZDaTtOQr1MCMcTS5nfNt-XQ9-9FocWp_ASW3ZQ4LPV8DqkkxSLdhTAmhR0BEx3RteMNyRFWEI26oQ4dPkP3rZbYMS76Ny_u5

docs/html/index.html

@@ -112,6 +112,7 @@ Functions receive the current stack, expression, and dictionary and return the n
 <p>The <strong>dictionary</strong> associates symbols (strings) with Joy expressions that define the
 available functions of the Joy system.  Together the stack, expression, and dictionary
 are the entire state of the Joy interpreter.</p>
+<p><img alt="joy_interpreter_flowchart.svg" src="/joy_interpreter_flowchart.svg"></p>
 <h3>Stack / Quote / List / Sequence</h3>
 <p>When talking about Joy we use the terms "stack", "quote", "sequence",
 "list", and others to mean the same thing: a simple linear datatype that