fixes logo copy

documentation/merge_doc_html.sh.in

@@ -7,6 +7,9 @@ rsync --archive \
 rsync --archive \
     @CMAKE_CURRENT_BINARY_DIR@/sphinx_html \
     @CMAKE_CURRENT_BINARY_DIR@/public/
+rsync --archive \
+    @PROJECT_SOURCE_DIR@/documentation/TurTLE_logo.svg \
+    @CMAKE_CURRENT_BINARY_DIR@/public/
 cp \
     @CMAKE_CURRENT_BINARY_DIR@/doc_full_index.html \
     @CMAKE_CURRENT_BINARY_DIR@/public/index.html