Cleaning up test cases

@anbangx 

This branch is WIP and isn't ready to merge yet.  Its purpose is to clean up the test cases so that travis-ci passes completely, meaning you should get a little green check mark below. The first commit cuts build and test time down from ~22 minutes to ~13 minutes.  I don't think we can shave this off any more since ~7 minutes are spent just downloading dependency jar files.

To run the tests yourself, follow the commands in `.travis.yml`.  Specifically, do:

```bash
sudo apt-get install graphviz
mvn install -q -am -pl genomix/genomix-driver/ -DskipTests=true
```

you should only have to do that once until we rebase onto a different hyracks master.  To test your own changes to the code, do:

```bash
cd genomix
mvn package -e
```

to get full details of the tests, check out the target/surefire-reports.  As in travis, you can get a dump of all those files with filename headers using `ls -t */target/surefire-reports/*.txt | xargs tail -n +1`