Declare escape strings for colored text (#1409)

* Color strings

* Color strings

* Color strings

* Color strings

* Color strings

* Color strings & fix first group scrolling off screen

* Color strings

* Color strings

* Clang

* Clang

* Clang attempt #3

* Update ui_painter.cpp

* Update ui_widget.cpp

* Clang test

* Clang

* Clang test

* Update ui_about_simple.cpp

* Update lge_app.cpp

firmware/common/ui.cpp

@@ -29,6 +29,7 @@
 namespace ui {
 
 // CGA palette
+// Index into this table should match STR_COLOR_ escape string in ui.hpp
 Color term_colors[16] = {
     Color::black(),
     Color::dark_blue(),