Simplify requirements.txt

Makefile

@@ -35,9 +35,7 @@ coverage: py_env
 py_env: requirements.txt setup.py
 	rm -rf py_env
 	virtualenv py_env
-	bash -c 'source py_env/bin/activate && \
+	bash -c 'source py_env/bin/activate && pip install -r requirements.txt'
-		pip install -e . && \
-		pip install -r requirements.txt'
 
 clean:
 	rm -rf py_env

requirements.txt

@@ -1,8 +1,4 @@
-argparse
+-e .
-jsonschema
-plumbum
-pyyaml
-simplejson
 
 # Testing requirements
 coverage