add api usage examples for cpp and python binding

bindings_python/CMakeLists.txt

@@ -6,6 +6,7 @@ set(PACKAGE_NAME "sourcetraildb")
 
 set(RESOURCES_SWIG_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../resources_swig")
 set(GENERATED_SRC_DIR "${CMAKE_CURRENT_BINARY_DIR}/src")
+set(PYTHON_BINDING_OUTPUT_DIR ${CMAKE_CURRENT_BINARY_DIR} PARENT_SCOPE)
 
 set(SWIG_INTERFACE_FILE "${RESOURCES_SWIG_DIR}/interface/${PACKAGE_NAME}.i")
 
@@ -35,7 +36,7 @@ swig_add_library(
 	${PACKAGE_NAME}
 	TYPE SHARED
 	LANGUAGE python
-	OUTPUT_DIR ${CMAKE_CURRENT_BINARY_DIR}
+	OUTPUT_DIR ${PYTHON_BINDING_OUTPUT_DIR}
 	OUTFILE_DIR ${GENERATED_SRC_DIR}
 	SOURCES ${SWIG_INTERFACE_FILE} ${RESOURCES_SWIG_DIR}/src/${PACKAGE_NAME}.cpp
 )