LibGfx: Add basic support for bidirectional text rendering

This adds a *very* simplified version of the UNICODE BIDIRECTIONAL
ALGORITHM (https://www.unicode.org/reports/tr9/), that can render most
bidirectional text but also produces awkward results in a large amount
of edge cases, and as such, this should probably be replaced with a
fully spec compliant implementation at some point.

Userland/Libraries/LibGfx/CMakeLists.txt

@@ -29,6 +29,7 @@ set(SOURCES
     Size.cpp
     StylePainter.cpp
     SystemTheme.cpp
+    TextDirection.cpp
     Triangle.cpp
     Typeface.cpp
     WindowTheme.cpp