Merge branch 'master' of github.com:opennetworkinglab/ngsdn-tutorial into vm

Author: ccascone

.gitignore

@@ -9,3 +9,5 @@ ptf/ptf.log
 ptf/ptf.pcap
 **/*.iml
 **/*.pyc
+**/*.bak
+util/.pipe_cfg

.travis.yml

@@ -0,0 +1,15 @@
+dist: xenial
+
+language: python
+
+services:
+  - docker
+
+python:
+  - "3.5"
+
+install:
+  - make pull-deps
+
+script:
+  - make check-solution