Add travis ci (#35)

* Add travis CI
* Add ci testing of example models (with python 2.7 as py3 still fails)
diff --git a/test/model/extensions/classes/first.yml b/test/model/extensions/classes/first.yml
new file mode 100644
index 0000000..96ece27
--- /dev/null
+++ b/test/model/extensions/classes/first.yml
@@ -0,0 +1,6 @@
+parameters:
+  _param:
+    some: param
+  lab:
+    name: test
+    label: first