Mvp git immersion

- added directory structure similar to saasbook/hw including placeholders for Readmes
- autograder test spec file
- feature that tests it
- install feature duped from saasbook/hw
- travis file a bit different than saasbook/hw

todo:
- eliminate dependency on my personal gitimmersion repo in username.txt, possibly git --local
- add xml file in autograder directory
- comment out debug line in install.feature 'Then I should see the execution results'