Added initial interfaces and some sensors implementing them

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/bh1750/bh1750.cxx

@@ -59,6 +59,11 @@ float BH1750::getLux()
   return lux;
 }
 
+float BH1750::getLuminance()
+{
+    return getLux();
+}
+
 void BH1750::powerUp()
 {
   if (bh1750_power_up(m_bh1750) != UPM_SUCCESS)

src/bh1750/bh1750.hpp

@@ -29,6 +29,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
+#include <interfaces/iLight.hpp>
 
 #include "bh1750.h"
 
@@ -57,7 +58,7 @@ namespace upm {
      * @snippet bh1750.cxx Interesting
      */
 
-  class BH1750 {
+  class BH1750 : virtual public iLight {
   public:
 
     /**
@@ -92,6 +93,13 @@ namespace upm {
      */
     float getLux();
 
+    /**
+     * Gets the luminance value from the sensor
+     *
+     * @return The measured light intensity value in Lux
+     */
+    virtual float getLuminance();
+
     /**
      * Power up the device.
      */