Added pip install -e . to travis config

Author: Mohan Kishore

.travis.yml

@@ -4,7 +4,10 @@ python:
 - 3.5
 - 3.4
 - 2.7
-install: pip install -r requirements.txt && pip install -U tox-travis
+install:
+- pip install -r requirements.txt
+- pip install -e .
+- pip install -U tox-travis
 script: tox
 deploy:
   provider: pypi