Various minor fixes (#4172)

- css tweaks: use correct CSS "hyphens:" instead of "hyphenate:"
- screenshoter: more logical order of lines (no change in what it does)
- textviewer: make diagonal swipe really trigger a full refresh
- textwidget: more adequate text length to help with centering
- toggleswitch: fix sizing & centering with correct calculations
  (this reduces a bit the size of switches, and may cause a new
  truncation in some translations)

frontend/ui/widget/textwidget.lua

@@ -46,7 +46,11 @@ function TextWidget:updateSize()
     if not tsize then
         self._length = 0
     else
-        self._length = math.ceil(tsize.x)
+        -- As text length includes last glyph pen "advance" (for positionning
+        -- next char), it's best to use math.floor() instead of math.ceil()
+        -- to get rid of a fraction of it in case this text is to be
+        -- horizontally centered
+        self._length = math.floor(tsize.x)
     end
     -- Used to be:
     --   self._height = math.ceil(self.face.size * 1.5)