Do not disable safe browsing by default (fixes #129)

- wrkey was removed quite some time ago, so tracking potential is lower
- safe browsing is for many people a good idea
- one might still want to disable it as it relies on thirdparties

So keep the option but unchecked by default.
The settings are also reduced to the master kill switch instead of
toggling all sub-options as well.

Author: allo-

settings/google_safebrowsing.json

@@ -2,20 +2,12 @@
     {
         "name": "google_safebrowsing", 
         "type": "boolean", 
-        "initial": true, 
+        "initial": false, 
         "label": "Disable google safebrowsing", 
-        "help_text": "Google safebrowsing can detect phishing and malware but it also sends informations to google together with an unique id called <a href=\"http://electroholiker.de/?p=1594\">wrkey</a>.", 
+        "help_text": "Google safebrowsing can detect phishing and malware but one might not want to rely on a URL list provided by Google.", 
         "addons": [], 
         "config": {
-            "browser.safebrowsing.enabled": false,
-            "browser.safebrowsing.downloads.remote.url": "", 
-            "browser.safebrowsing.phishing.enabled": false, 
-            "browser.safebrowsing.blockedURIs.enabled": false, 
-            "browser.safebrowsing.downloads.enabled": false,
-            "browser.safebrowsing.downloads.remote.enabled": false,
-            "browser.safebrowsing.appRepURL": "", 
-            "browser.safebrowsing.malware.enabled": false
-
+            "browser.safebrowsing.enabled": false
         }
     }
 ]