Adding the stub of the after_script section

The $TRAVIS_BUILD_DIR; needs to be set and commands run from outside of root in future.
Moving before_script to bash file

This is only a stub no actual changes will take effect for the tests. Additional documentation of variables
Stub code for build_script

This is the same as the script: directive in .travis.yml
Moving the install tasks to the install.sh
Update .travis.yml
Update .travis.yml
Merge pull request #6 from pantheon-learning/afterbuild

Adding code to build_script.sh, before_script.sh, after_script.sh, install.sh