read global default value for using embedded stylesheets

The global configuration wasn't evaluated before.
Fixes #1364.

frontend/apps/reader/modules/readertypeset.lua

@@ -27,9 +27,15 @@ function ReaderTypeset:onReadSettings(config)
         self.css = self.ui.document.default_css
     end
 
-    -- default to enable embedded css
     self.embedded_css = config:readSetting("embedded_css")
-    if self.embedded_css == nil then self.embedded_css = true end
+    if self.embedded_css == nil then
+        -- default to enable embedded css
+        -- note that it's a bit confusing here:
+        -- global settins store 0/1, while document settings store false/true
+        -- we leave it that way for now to maintain backwards compatibility
+        local global = G_reader_settings:readSetting("copt_embedded_css")
+        self.embedded_css = (global == nil or global == 1) and true or false
+    end
     self.ui.document:setEmbeddedStyleSheet(self.embedded_css and 1 or 0)
 
     -- set page margins