Merge remote-tracking branch 'tstone/upstream'

test/cases/github-style-linebreaks.html

@@ -0,0 +1,4 @@
+
+<pre><code>code can go here
+this is rendered on a second line
+</code></pre>

test/cases/github-style-linebreaks.md

@@ -0,0 +1,4 @@
+```
+code can go here
+this is rendered on a second line
+```