Add font size selection to ecode font picker:

Allow UIFontPickerDialog sections to be hidden and make ecode's UI, editor, and terminal font dialogs select both the font and its size.
Keep external fonts selectable across asynchronous font enumeration, including when they share a family name with a system font, and label them as external. Also normalize UILinearLayout weights across visible children so hidden picker columns release their space correctly.
Update font picker previews, size units, menu labels, translations, and lifetime handling.

Addresses SpartanJ/ecode#944.

src/tools/ecode/ecode.cpp

@@ -442,9 +442,9 @@ void App::openFolderDialog() {
 }
 
 void App::openFontDialog( std::string& fontPath, bool loadingMonoFont, bool terminalFont,
-						  std::function<void()> onFinish ) {
+						  std::function<void()> onFinish, bool pickFontSize ) {
 	mFontPickerController->openFontDialog( fontPath, loadingMonoFont, terminalFont,
-										   std::move( onFinish ) );
+										   std::move( onFinish ), pickFontSize );
 }
 
 void App::updateInputFonts() {