Refactor and modernize namespace declarations

Move all unit tests to namespace nfd::tests

Delete unused header core/algorithm.hpp

Change-Id: I5591f0c5f3bb5db67f8b45fae95471f8a555ca68
diff --git a/daemon/fw/asf-measurements.cpp b/daemon/fw/asf-measurements.cpp
index c49f5d5..df1f4ff 100644
--- a/daemon/fw/asf-measurements.cpp
+++ b/daemon/fw/asf-measurements.cpp
@@ -26,9 +26,7 @@
 #include "asf-measurements.hpp"
 #include "common/global.hpp"
 
-namespace nfd {
-namespace fw {
-namespace asf {
+namespace nfd::fw::asf {
 
 time::nanoseconds
 FaceInfo::scheduleTimeout(const Name& interestName, scheduler::EventCallback cb)
@@ -142,6 +140,4 @@
   m_measurements.extendLifetime(me, MEASUREMENTS_LIFETIME);
 }
 
-} // namespace asf
-} // namespace fw
-} // namespace nfd
+} // namespace nfd::fw::asf