Added samtools as a dependency in travis installation

Author: alneberg

.travis.yml

@@ -13,7 +13,7 @@ services:
 before_install:
    - pip install --upgrade pip
    - sudo apt-get update -qq
-   - sudo apt-get install -qq build-essential libgsl0-dev bedtools mummer
+   - sudo apt-get install -qq build-essential libgsl0-dev bedtools mummer samtools
    - "export DISPLAY=:99.0"
    - pip install -r requirements.txt
    - wget https://github.com/BinPro/integration_test_data/archive/v1.0.tar.gz