Add Mobilenet2SSDLite test

The new test works both with TensorRT and cuDNN. Preprocessing and
Postprocessing are missing. Add ClippedReLU (for ReLU6), groups for
Conv2d, additional bias for convolution.

Other minors:
-move the timer in the detector to measure all the
processing time for a given frame (both centernet and yolo);
-add int8 flag.

Signed-off-by: Micaela Verucchi <micaelaverucchi@gmail.com>
Davide Sapienza <sapienza.dav@gmail.com>

include/tkDNN/Network.h

@@ -59,7 +59,7 @@ public:
     dataDim_t input_dim;
     dataDim_t getOutputDim();
 
-    bool fp16, dla;
+    bool fp16, dla, int8;
     bool dontLoadWeights;
 };