TextLayout: Use new shaping engine

By utilising ShapedText in the TextLayout implementation.

BREAKING_CHANGES.md

@@ -2,6 +2,38 @@
 
 # Version 8.0.0
 
+## Change
+
+As part of the Unicode upgrades the vertical alignment logic of TextLayout has
+been altered. Lines containing text written in multiple different fonts will
+now have their baselines aligned. Additionally, using the
+Justification::verticallyCentred or Justification::bottom flags may now result
+in the text being positioned slightly differently.
+
+**Possible Issues**
+
+User interfaces using TextLayout with texts drawn using multiple fonts will now
+have their look changed.
+
+**Workaround**
+
+There is no workaround.
+
+**Rationale**
+
+The old implementation had incosistent vertical alignment behaviour. Depending
+on what exact fonts the first line of text happened to use, the bottom alignment
+would sometimes produce unnecessary padding on the bottom. With certain text and
+Font combinations the text would be drawn beyond the bottom boundary even though
+there was free space above the text.
+
+The same amount of incorrect vertical offset, that was calculated for bottom
+alignment, was also present when using centred, it just wasn't as apparent.
+
+Not having the baselines aligned between different fonts resulted in generally
+displeasing visuals.
+
+
 ## Change
 
 The virtual functions LowLevelGraphicsContext::drawGlyph() and drawTextLayout()