Move the sensor utils into their own module

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I22f6a951921095660fd2be502e59a38161565a95
diff --git a/Makefile.am b/Makefile.am
index 2daf76f..edbebfa 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -56,7 +56,7 @@
 	$(PHOSPHOR_LOGGING_CFLAGS) \
 	$(CODE_COVERAGE_CXXFLAGS)
 
-swampd_SOURCES = main.cpp util.cpp
+swampd_SOURCES = main.cpp
 swampd_LDADD = \
 	$(SDBUSPLUS_LIBS) \
 	libswampd.la
@@ -94,6 +94,7 @@
 	sensors/builder.cpp \
 	sensors/buildjson.cpp \
 	sensors/manager.cpp \
+	sensors/build_utils.cpp \
 	pid/ec/pid.cpp \
 	pid/ec/stepwise.cpp \
 	pid/fancontroller.cpp \