Fix up the pom file for my hosting.

Fix up the pom file, preparing it to be used to deploy to Maven Central.
Also fix up some whitespace issues, and lock the versions of all used plugins,
since maven couldn't apparently figure out which versions to use.
Remove some extra files that are not used.

Remove some old tests file that are not used, along with a pre-compiled jar
file that came from somewhere.
Add IntelliJ IDEA files to the .gitignore file.

Also ignore the IntelliJ IDEA files.
When multiple empty keys are found, make sure they are all stored in the output.

Even though most users won't run against this, in case multiple empty keys are
found, store them all under @? where ? is a 0-starting index.  Also include a
modified MATLAB file to test these conditions.  Note that MATLAB just ignores
all three inputs.
Add a .travis.yml file, to enable Travis CI.

Get this going for sanity checks.  Test against both JDK 6 and 7.