Add CMake support for also building Markdown docs in parallel (#49)

docs/CMakeLists.txt

@@ -0,0 +1,24 @@
+# Find Sphinx
+include(SetupSphinx)
+setup_sphinx_environment()
+
+set(SPHINX_SOURCE ${CMAKE_CURRENT_SOURCE_DIR}/source)
+set(SPHINX_BUILD ${CMAKE_BINARY_DIR})
+
+# Build HTML documentation
+add_custom_target(html
+    COMMAND ${SPHINX_EXECUTABLE} -b html ${SPHINX_SOURCE} ${SPHINX_BUILD}
+    COMMENT "Building HTML documentation"
+    VERBATIM
+)
+
+# Build markdown documentation
+add_custom_target(markdown
+    COMMAND ${SPHINX_EXECUTABLE} -b markdown ${SPHINX_SOURCE} ${SPHINX_BUILD}
+    COMMENT "Building Markdown documentation"
+    VERBATIM
+)
+
+# Build both formats
+add_custom_target(docs ALL)
+add_dependencies(docs html markdown)