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/frc971/analysis/in_process_plotter.cc b/frc971/analysis/in_process_plotter.cc
index b327c54..b537aa4 100644
--- a/frc971/analysis/in_process_plotter.cc
+++ b/frc971/analysis/in_process_plotter.cc
@@ -2,8 +2,7 @@
 
 #include "aos/configuration.h"
 
-namespace frc971 {
-namespace analysis {
+namespace frc971::analysis {
 
 namespace {
 const char *kDataPath = "frc971/analysis/cpp_plot";
@@ -168,5 +167,4 @@
   next_top_ = 0;
 }
 
-}  // namespace analysis
-}  // namespace frc971
+}  // namespace frc971::analysis