python: Support building of both python2 & python3 bindings

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/python/python2/CMakeLists.txt

@@ -0,0 +1,39 @@
+set_source_files_properties (mraa2.i PROPERTIES CPLUSPLUS ON)
+set_source_files_properties (mraa2.i PROPERTIES SWIG_FLAGS "-I${CMAKE_BINARY_DIR}/src")
+
+if (PYTHON2_LIBRARY)
+    message ("PYTHON2 attempting to build!")
+
+    swig_add_module (python2-mraa python mraa2.i ../mraapy.c)
+    swig_link_libraries (python2-mraa ${PYTHON2_LIBRARIES} mraa)
+    
+    target_include_directories(${SWIG_MODULE_python2-mraa_REAL_NAME}
+      PUBLIC
+      "${CMAKE_CURRENT_SOURCE_DIR}/../.."
+      "${PYTHON2_INCLUDE_DIR}"
+    )
+
+    if (DOXYGEN_FOUND AND PYTHON2_EXECUTABLE)
+      foreach (_file ${DOCCLASSES})
+        add_dependencies (${SWIG_MODULE_python2-mraa_REAL_NAME} ${_file}class_doc_i)
+      endforeach ()
+      add_dependencies (${SWIG_MODULE_python2-mraa_REAL_NAME} common_hpp_doc_i)
+
+      add_custom_target (pydoc
+        pydoc -w ${CMAKE_CURRENT_BINARY_DIR}/mraa.py ${CMAKE_CURRENT_BINARY_DIR}/
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+        COMMENT "Generating API documentation with pydoc" VERBATIM
+      )
+    endif ()
+
+    set_target_properties (${SWIG_MODULE_python2-mraa_REAL_NAME} PROPERTIES
+      OUTPUT_NAME _mraa
+      COMPILE_FLAGS "${CMAKE_C_FLAGS} -DSWIGPYTHON=${SWIG_FOUND}"
+    )
+
+    install (FILES ${CMAKE_CURRENT_BINARY_DIR}/_mraa.so
+             ${CMAKE_CURRENT_BINARY_DIR}/mraa.py
+             DESTINATION ${CMAKE_INSTALL_PREFIX}/${PYTHON2_PACKAGES_PATH})
+endif()
+
+add_subdirectory (docs)