CSS Filter: allow text-size-adjust and appearance.

New allowed property: `appearance`. Used to normalize text inputs
in webkit browsers:
http://stackoverflow.com/questions/7599533/ios-forces-rounded-corners-and-glare-on-inputs.

New allowed property: `text-size-adjust`. Used to stop iOS from
enlarging text automatically:
http://css-tricks.com/prevent-iphone-text-enlargement/.

r2/r2/lib/cssfilter.py

@@ -83,6 +83,7 @@
     "animation-name",
     "animation-play-state",
     "animation-timing-function",
+    "appearance",
     "backface-visibility",
     "background",
     "background-attachment",
@@ -258,6 +259,7 @@
     "text-overflow",
     "text-rendering",
     "text-shadow",
+    "text-size-adjust",
     "text-space-collapse",
     "text-transform",
     "text-underline-position",