Add zoomlevels to config

qutebrowser/qutebrowser.conf

@@ -27,12 +27,16 @@
 #                 true/naive: Use simple/naive check
 #                 dns:        Use DNS matching (might be slow)
 #                 false:      Never search automatically
+# zoomlevels: The available zoom levels (taken from Chrome), separated by ","
+# defaultzoom: The default zoom level
 show_completion = true
 completion_height = 50%
 ignorecase = true
 wrapsearch = true
 startpage = http://www.duckduckgo.com/
 auto_search = naive
+zoomlevels = 25,33,50,67,75,90,100,110,125,150,175,200,250,300,400,500
+defaultzoom = 100
 
 [tabbar]
 # movable: bool, whether tabs should be movable