Remove the C++ code and refine Python code.

Author: qingqing01

CMakeLists.txt

@@ -43,7 +43,6 @@ option(WITH_SWIG_PY "Compile PaddlePaddle with py PaddlePaddle prediction api" $
 option(ON_TRAVIS "Running test on travis-ci or not." OFF)
 option(ON_COVERALLS "Generating code coverage data on coveralls or not." OFF)
 option(COVERALLS_UPLOAD "Uploading the generated coveralls json." ON)
-option(USE_OPENCV "Compile PaddlePaddle with opencv" OFF)
 
 if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING 
@@ -196,7 +195,3 @@ if(WITH_DOC)
     add_subdirectory(doc)
     add_subdirectory(doc_cn)
 endif()
-
-if(USE_OPENCV)
-    add_subdirectory(plugin/opencv)
-endif()