Update dev requirement installation

Also cleanup travis installation

@@ -4,8 +4,8 @@ python:
   - "3.3"
   - "3.4"
   - "3.5"
+cache: pip
 install:
-  - pip install -r requirements.txt
-  - pip install coverage python-coveralls
+  - pip install -r requirements-dev.txt
 script: nosetests tests/unit --cover-erase --with-coverage --cover-package kappa
 after_success: coveralls

-boto3>=1.2.3
-placebo>=0.8.1
-click>=5.1
-PyYAML>=3.11
+-r requirements.txt
+coverage==4.1
 mock>=1.0.1
 nose==1.3.1
+python-coveralls==2.7.0
+requests==2.10.0
+sh==1.11
 tox==1.7.1

+PyYAML>=3.11
 boto3>=1.2.3
-placebo>=0.8.1
 click>=5.1
-PyYAML>=3.11
+placebo>=0.8.1