travis: test on both py27 and py35; drop py34 as it's redundant

install deps from requirements.txt

no need to install cu2qu to run `setup.py test`.

.travis.yml

@@ -1,15 +1,14 @@
 sudo: false
 language: python
 python:
-  - "3.4"
+  - "2.7"
+  - "3.5"
 branches:
   only:
     - master
 
 install:
-  - python setup.py install
-  - pip install git+https://github.com/behdad/fonttools
-  - pip install git+https://github.com/unified-font-object/ufoLib
+  - pip install -r requirements.txt
 
 script:
   - python setup.py test