Add changelog file

CHANGELOG

@@ -0,0 +1,33 @@
+# Changelog
+
+## Next version: 0.8.0
+
+### New features
+
+- Style
+    - Add support for bold/italic/underlined text
+    - Added `StyledString` for markup text
+- Buttons:
+    - Added `Dialog::buttons` to iterate on buttons
+    - Added `Button::set_label` and `Button::label`
+- TextView:
+    - Add TextContent, a way to separate model and view for TextView
+    - Add manual scrolling methods
+- Allow multiple global callbacks per event
+- Allow buttons and delimiters in top-level menubar
+- StackView:
+    - Added `StackView::move_layer`
+    - `StackView::pop_layer` now returns the pop'ed view
+
+### Bugfixes
+
+- Fix a bug in `TextArea::set_content`
+- Fix `Color::from_256colors` for grayscale colors
+- Fix resize detection on windows
+
+### Doc
+
+- Add per-distributions instructions to install ncurses
+- Improved comments in examples
+- Improve doc for `Cursive::find_id`
+- Improve doc for `Identifiable::with_id`