Remove examples workaround in Makefile.

docs/Makefile

@@ -16,9 +16,5 @@ help:
 
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
-%: Makefile examples
+%: Makefile
 	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
-
-examples:
-	cp ../examples/notebooks/*ipynb source/examples/examples_api
-