Nest all namespaces

The compiler supports this now.  We can type less going forward.
No functional changes.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I29d6fa4f9aacc0e381f1a7637294db0392466995
diff --git a/motors/math.cc b/motors/math.cc
index 574ef9a..5eac813 100644
--- a/motors/math.cc
+++ b/motors/math.cc
@@ -2,8 +2,7 @@
 
 #include <math.h>
 
-namespace frc971 {
-namespace motors {
+namespace frc971::motors {
 namespace math_internal {
 
 float sin_float_table[SinCosFloatTableSize() + 1]
@@ -35,5 +34,4 @@
   }
 }
 
-}  // namespace motors
-}  // namespace frc971
+}  // namespace frc971::motors