- Added CMake target "apidoc" for creating Doxygen API documentation

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3d42fa4..bb858e8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,3 +17,7 @@
 add_subdirectory(include)
 add_subdirectory(tests)
 add_subdirectory(programs)
+
+ADD_CUSTOM_TARGET(apidoc
+                  COMMAND doxygen Doxyfile
+                  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})