added example/opencv_convolution.cpp
added opencv sobel filter
added return in catch block
Merge pull request #150 from Mageswaran1989/adding-opencv_convolution.cpp-example

added example/opencv_convolution.cpp
added return in catch block

Conflicts:
	example/CMakeLists.txt
Merge pull request #151 from Mageswaran1989/adding-opencv_sobel_filter-example

added opencv sobel filter

Conflicts:
	example/CMakeLists.txt