Correct new line numbers in diff viewer

With each new hunk, starting new line number was the same as starting old
line number. Parse diff line a bit further to get real new line number.

Fix HREFs for old line number links in both bootstrap3 and default themes
so that thay work.

themes/bootstrap3/twig/commit.twig

@@ -46,7 +46,7 @@
                 <td class="lineNo">
                     {% if line.getType != 'chunk' %}
                         <a name="L{{ loop.index }}R{{ line.getNumOld }}"></a>
-                        <a href="#L{{ loop.index }}L{{ line.getNumOld }}">
+                        <a href="#L{{ loop.index }}R{{ line.getNumOld }}">
                     {% endif %}
                     {{ line.getNumOld }}
                     {% if line.getType != 'chunk' %}