feat(lib): add support for presenter notes (#322)

* feat(lib): add support for presenter notes

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix(test): typo

* Update test_slide.py

* Update convert.py

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

tests/test_slide.py

@@ -196,6 +196,34 @@ class TestSlide:
 
             assert self._base_slide_config.playback_rate == 2.0
 
+    @assert_constructs
+    class TestReversedPlaybackRate(Slide):
+        def construct(self) -> None:
+            text = Text("Some text")
+
+            self.add(text)
+
+            assert self._base_slide_config.reversed_playback_rate == 1.0
+
+            self.next_slide(reversed_playback_rate=2.0)
+            self.play(text.animate.scale(2))
+
+            assert self._base_slide_config.reversed_playback_rate == 2.0
+
+    @assert_constructs
+    class TestNotes(Slide):
+        def construct(self) -> None:
+            text = Text("Some text")
+
+            self.add(text)
+
+            assert self._base_slide_config.notes == ""
+
+            self.next_slide(notes="test")
+            self.play(text.animate.scale(2))
+
+            assert self._base_slide_config.notes == "test"
+
     @assert_constructs
     class TestWipe(Slide):
         def construct(self) -> None: