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-probing-module.cpp b/daemon/fw/asf-probing-module.cpp
index 0df1712..25e0ac3 100644
--- a/daemon/fw/asf-probing-module.cpp
+++ b/daemon/fw/asf-probing-module.cpp
@@ -29,9 +29,7 @@
 
 #include <ndn-cxx/util/random.hpp>
 
-namespace nfd {
-namespace fw {
-namespace asf {
+namespace nfd::fw::asf {
 
 static_assert(ProbingModule::DEFAULT_PROBING_INTERVAL < AsfMeasurements::MEASUREMENTS_LIFETIME);
 
@@ -178,6 +176,4 @@
   }
 }
 
-} // namespace asf
-} // namespace fw
-} // namespace nfd
+} // namespace nfd::fw::asf