Allow constexpr, and use it in a few places.

styleguide/c++/c++11.html

Index: styleguide/c++/c++11.html
diff --git a/styleguide/c++/c++11.html b/styleguide/c++/c++11.html
index 8ba681ed80d5b47b8ded80d6cd731d967c100019..e592cb40de7847708c7dd04f0f75ad7164d2bb85 100644
--- a/styleguide/c++/c++11.html
+++ b/styleguide/c++/c++11.html
@@ -110,6 +110,14 @@ Style Guide on <code>auto</code></a>. <a href="https://groups.google.com/a/chrom
 </tr>
 
 <tr>
+<td>Constant Expressions</td>
+<td><code>constexpr</code></td>
+<td>Compile-time constant expressions</td>
+<td><a href="http://en.cppreference.com/w/cpp/language/constexpr">constexpr specifier</a></td>
+<td>Prefer to <code>const</code> for variables where possible. Use cautiously on functions. Don't go out of the way to convert existing code. <a href="https://google.github.io/styleguide/cppguide.html#Use_of_constexpr">Google Style Guide</a></td>
+</tr>
+
+<tr>
 <td>Declared Type Accessor</td>
 <td><code>decltype(<i>expression</i>)</code></td>
 <td>Provides a means to determine the type of an expression at compile-time,
@@ -550,17 +558,6 @@ supports them</a>; reevaluate after MSVS2015 is available.
 </tr>
 
 <tr>
-<td>Constant Expressions</td>
-<td><code>constexpr</code></td>
-<td>Compile-time constant expressions</td>
-<td><a href="http://en.cppreference.com/w/cpp/language/constexpr">
-constexpr specifier</a></td>
-<td>Doesn't work in MSVS2013. Reevalute once it does. <a
-href="https://google.github.io/styleguide/cppguide.html#Use_of_constexpr">Google
-Style Guide on <code>constexpr</code></a></td>
-</tr>
-
-<tr>
 <td>Function Local Variable</td>
 <td><code>__func__</code></td>
 <td>Provides a local variable of the name of the enclosing