Theme manifest key updates

Changes to account for the fact that "headerURL":, "accentcolor":, and "textcolor": have been replaced by "theme_frame": , "frame":, and "tab_text": respectively.  In addition, removed the empty.png image files, as these are no longer needed. Also added an example of use of theme_inactive to weta_tiled.

themes/weta_mirror/manifest.json

@@ -3,12 +3,11 @@
   "description": "Theme using multiple additional_backgrounds images. See https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Examples#themes",
   "manifest_version": 2,
   "name": "weta_mirror",
-  "version": "1.0",
+  "version": "1.1",
   "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/themes/weta_mirror",
 
   "theme": {
     "images": {
-      "headerURL": "empty.png",
       "additional_backgrounds": [ "weta.png", "weta-left.png"]
     },
 
@@ -17,8 +16,8 @@
     },
     
     "colors": {
-       "accentcolor": "#adb09f",
-       "textcolor": "#000"
+       "frame": "#adb09f",
+       "tab_text": "#000"
     }
   }
 }