Merge pull request #347 from mutalyzer/travis-no-sudo

Travis updates

.travis.yml

 # Validate this file using http://lint.travis-ci.org/
 language: python
+sudo: false
+cache: pip
 python: "2.7"
 addons:
+  apt_packages: swig
   postgresql: "9.4"
 services: redis-server
 before_install:
-  - sudo apt-get update -qq
-  - sudo apt-get install -y swig
   - CFLAGS=-O0 pip install -r requirements.txt
   - pip install psycopg2
 install: pip install .