sensors/zones: place in namespace and cleanup

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I527dbc8477a232945f696227a7b0b2adbee45175
diff --git a/conf.hpp b/conf.hpp
index 559afaa..428d446 100644
--- a/conf.hpp
+++ b/conf.hpp
@@ -7,6 +7,8 @@
 #include <string>
 #include <vector>
 
+namespace pid_control
+{
 namespace conf
 {
 
@@ -59,3 +61,4 @@
 using PIDConf = std::map<std::string, struct ControllerInfo>;
 
 } // namespace conf
+} // namespace pid_control