OpenCV: a sample program

A simple program compilation on Ubuntu 12.04. There is an annoying issue where the placement of libraries has to happen before the object needing them. Correct format.

• g++:
• g++ `pkg-config --cflags opencv` test.cpp `pkg-config --libs opencv` -o test
• Makefile:
•  executable: test.o
      g++ -o executable test.o `pkg-config --libs opencv`
     
  test.o:
      g++ `pkg-config --cflags opencv` -c test.cpp