Add build status (travis) to readme.md

.travis.yml

@@ -3,13 +3,11 @@ compiler:
   - clang
 
 before_install:
-  - sudo apt-get update
-  - sudo apt-get install libpcre3 libpcre3-dev
-  - sudo apt-get install swig
-  - sudo apt-get install doxygen
-  - sudo apt-get install python-numpy
-  - sudo apt-get install python-scipy
-  - sudo apt-get install python-nose
+  - sudo apt-get update -qq
+  - sudo apt-get install -qq libpcre3 libpcre3-dev gromacs
+  - sudo apt-get install -qq swig doxygen
+  - sudo apt-get install -qq python-numpy python-scipy python-nose
+
 script:
   - cmake -DCMAKE_INSTALL_PREFIX=~/OpenMM . 
   - make 

README.md

 ## OpenMM: A High Performance Molecular Dynamics Library
 
+[![Build Status](https://travis-ci.org/SimTk/openmm.png?branch=master)](https://travis-ci.org/SimTk/openmm)
+
 Introduction
 ------------