fix/add build

MANIFEST.in

@@ -0,0 +1,3 @@
+include README.md
+include requirements.txt
+include ocrd-tool.json

Makefile

@@ -20,6 +20,7 @@ help:
 	@echo "    deps-ubuntu  Install required packages for Debian/Ubuntu"
 	@echo "    install      Install"
 	@echo "    install-dev  Install in editable mode"
+	@echo "    build        Build source and binary distribution"
 	@echo "    docker       Build Docker image"
 	@echo "    test         Run test"
 	@echo "    repo/assets  Clone OCR-D/assets to ./repo/assets"
@@ -54,6 +55,10 @@ install:
 install-dev:
 	$(PIP) install -e .
 
+build:
+	$(PIP) install build
+	$(PYTHON) -m build .
+
 # Build docker image
 docker:
 	docker build \