enable unit-tests: enable for SensorManager

Enabled unit-tests in general for the project, and more
specifically started with a benign construction test for
the SensorManager object.

Tested: Verified continues to build and link, and unit-test
passes.
Tested: Ran on quanta-q71l board and it behaved as expected.

Change-Id: I4ad9a0c57efd0b9ccc37d26faa0cc1b82026b8d7
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/sensors/builderconfig.cpp b/sensors/builderconfig.cpp
index b3507ae..f1d95a0 100644
--- a/sensors/builderconfig.cpp
+++ b/sensors/builderconfig.cpp
@@ -16,6 +16,8 @@
 
 #include <iostream>
 #include <libconfig.h++>
+#include <string>
+#include <unordered_map>
 
 /* Configuration. */
 #include "conf.hpp"
@@ -28,7 +30,7 @@
  * parsing.  I should just ditch the compile-time version to reduce the
  * probability of sync bugs.
  */
-std::shared_ptr<SensorManager> BuildSensorsFromConfig(const std::string& path)
+SensorManager BuildSensorsFromConfig(const std::string& path)
 {
     using namespace libconfig;