Improve modules code and add a requirements variable

source/modules/FilterFrame.cpp

@@ -35,12 +35,12 @@ PlaYUVerModuleDefinition FilterFrameDef = {
     "Filters",
     "Y_Filter",
     "Filter Y matrix of YUV frame",
-    false,
+    MODULE_REQUIRES_FRAME,
 };
 
 FilterFrame::FilterFrame()
 {
-  m_cModuleDef = FilterFrameDef;
+  setModuleDefinition( FilterFrameDef );
   m_pcFilteredFrame = NULL;
 }
 

source/modules/FrameDifference.cpp

@@ -36,12 +36,13 @@ static PlaYUVerModuleDefinition FrameDifferenceDef =
     "Measurements",
     "FrameDifference",
     "Measure the difference between two images (Y plane)",
-    true, };
+    MODULE_REQUIRES_TWOFRAMES | MODULE_REQUIRES_NEW_WINDOW,
+};
 
 FrameDifference::FrameDifference()
 {
   m_pcFrameDifference = NULL;
-  m_cModuleDef = FrameDifferenceDef;
+  setModuleDefinition( FrameDifferenceDef );
 }
 
 Void FrameDifference::create( PlaYUVerFrame* Input )

source/modules/MeasurePSNR.cpp

@@ -35,13 +35,14 @@ static PlaYUVerModuleDefinition MeasurePSNRDef =
     FRAME_LEVEL_MODULE,
     "Measurements",
     "PSNR",
-    "MEasure the PSNR between two images",
-    true, };
+    "Measure the PSNR between two images",
+    MODULE_REQUIRES_TWOFRAMES | MODULE_REQUIRES_SIDEBAR,
+};
 
 MeasurePSNR::MeasurePSNR()
 {
   m_pcFilteredFrame = NULL;
-  m_cModuleDef = MeasurePSNRDef;
+  setModuleDefinition( MeasurePSNRDef );
 }
 
 Void MeasurePSNR::create( PlaYUVerFrame* InputFrame )