Force after_all hooks to run on fail-fast

Resolves issues #2.

src/spectator/example_group.cr

@@ -157,9 +157,10 @@ module Spectator
     # The hooks will be run only once,
     # and only after all examples in the group have finished.
     # Subsequent calls after the hooks have been run will do nothing.
-    protected def run_after_all_hooks : Nil
+    protected def run_after_all_hooks(ignore_unfinished = false) : Nil
       return if @after_all_hooks_run
-      return unless finished?
+      return unless ignore_unfinished || finished?
+
       @hooks.run_after_all
       @after_all_hooks_run = true
     end

src/spectator/nested_example_group.cr

@@ -51,9 +51,9 @@ module Spectator
     # and only after all examples in the group have finished.
     # Subsequent calls after the hooks have been run will do nothing.
     # Parent "after-all" hooks will be run last.
-    protected def run_after_all_hooks : Nil
+    protected def run_after_all_hooks(ignore_unfinished = false) : Nil
       super
-      parent.run_after_all_hooks
+      parent.run_after_all_hooks(ignore_unfinished)
     end
 
     # Runs all of the "after-each" hooks.

src/spectator/runner.cr

@@ -34,7 +34,10 @@ module Spectator
       example_order.each do |example|
         result = run_example(example).as(Result)
         results << result
-        break if @config.fail_fast? && result.is_a?(FailedResult)
+        if @config.fail_fast? && result.is_a?(FailedResult)
+          example.group.run_after_all_hooks(ignore_unfinished: true)
+          break
+        end
       end
     end