Update Makefile and requirements.

Makefile

 PROJECT = jetconf
-YANGSON_URL = https://gitlab.labs.nic.cz/llhotka/yangson.git
+.PHONY = tags deps install-deps
 
 tags:
 	find $(PROJECT) -name "*.py" | etags -
@@ -8,7 +8,4 @@ deps:
 	pip freeze > requirements.txt
 
 install-deps:
-	pip install --upgrade -r requirements.txt
-
-yangson:
-	pip install --upgrade git+$(YANGSON_URL)
+	pip install -r requirements.txt

requirements.txt

@@ -15,4 +15,6 @@ six==1.10.0
 snowballstemmer==1.2.1
 Sphinx==1.3.5
 sphinx-rtd-theme==0.1.9
-typing==3.5.0.1
+PyXB==1.2.5
+yangson==1.0.0
+-e .