several lints fixed that were detected by facebook's flint

Plugins/BasePlugin.h

@@ -28,10 +28,14 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef BASEPLUGIN_H_
 #define BASEPLUGIN_H_
 
+#include "../Util/StringUtil.h"
+
 #include <osrm/Coordinate.h>
 #include <osrm/Reply.h>
 #include <osrm/RouteParameters.h>
 
+#include <boost/foreach.hpp>
+
 #include <string>
 #include <vector>
 

Plugins/NearestPlugin.h

@@ -41,7 +41,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 template<class DataFacadeT>
 class NearestPlugin : public BasePlugin {
 public:
-    NearestPlugin(DataFacadeT * facade )
+    explicit NearestPlugin(DataFacadeT * facade )
      :
         facade(facade),
         descriptor_string("nearest")

Plugins/TimestampPlugin.h

@@ -33,7 +33,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 template<class DataFacadeT>
 class TimestampPlugin : public BasePlugin {
 public:
-    TimestampPlugin(const DataFacadeT * facade)
+    explicit TimestampPlugin(const DataFacadeT * facade)
      : facade(facade), descriptor_string("timestamp")
     { }
     const std::string & GetDescriptor() const { return descriptor_string; }

Plugins/ViaRoutePlugin.h

@@ -53,7 +53,7 @@ private:
     SearchEngine<DataFacadeT> * search_engine_ptr;
 public:
 
-    ViaRoutePlugin(DataFacadeT * facade)
+    explicit ViaRoutePlugin(DataFacadeT * facade)
      :
         descriptor_string("viaroute"),
         facade(facade)