Refactor: tried to refactor code

- move scripts to assets/scripts (and updated build)
 - put most logic into HaproxyConfigGenerator
 - created DockerLabelHandler for all label handling from previous code
 - added unit tests and fixtures to cover HaproxyConfigGenerator and DockerLabelHandler
 - added a Makefile with build (for docker build) and test targets

tests/context.py

@@ -0,0 +1,5 @@
+import os
+import sys
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
+import easymapping