Cross-browser layout accessibility and bug

* Adjust viewport tag to ask Mobile Chrome 32+ to disable click-delay
  (and therefore double-tap zoom) but *not* pinch-zoom. This makes mobile
  sites more responsive to interaction but doesn't damage accessibilty.
* Update the Responsive Layout article with this viewport tag (but is full
  purpose is to be explained in a later article).
* Stop Safari (Mac and iOS) from hyphenating and wrapping text in <pre>s.
  I belive I found a bug: https://bugs.webkit.org/show_bug.cgi?id=131031