v0.11.0: Plugin / Slot system

- defslot: register render functions into named slots with ordering
- slot-render: call all registered render-fns for a slot
- Slot modes designed (stack/replace/single-winner) but mode dispatch
  is implicit via the registration API
- slot-p, clear-slot, list-slots for lifecycle management
- Slots stored in a hash table keyed by string (equal test)
- 4 tests, 100% passing

tests/slot-tests.lisp

@@ -0,0 +1,26 @@
+(defpackage :cl-tty-slot-test (:use :cl :cl-tty.slot :fiveam))
+(in-package :cl-tty-slot-test)
+
+(def-suite slot-suite :description "Slot system tests")
+(in-suite slot-suite)
+
+(def-test defslot-register ()
+  (clear-slot :test-slot)
+  (defslot :test-slot :order 1 :render-fn (lambda () "hello"))
+  (is-true (slot-p :test-slot)))
+
+(def-test slot-render-calls ()
+  (clear-slot :test-slot)
+  (defslot :test-slot :order 1 :render-fn (lambda () "a"))
+  (defslot :test-slot :order 2 :render-fn (lambda () "b"))
+  (is (equal '("a" "b") (slot-render :test-slot))))
+
+(def-test slot-render-empty ()
+  (clear-slot :ghost)
+  (is-false (slot-render :ghost)))
+
+(def-test clear-slot-removes ()
+  (clear-slot :test-slot)
+  (defslot :test-slot :order 1 :render-fn (lambda () "x"))
+  (clear-slot :test-slot)
+  (is-false (slot-p :test-slot)))