New structure

A new project structure for Crawljax, fixing #87 and #81.

Crawljax now has several modules:

* **core**: Has all the core stuff. This is the dependency you import if you run crawljax via a main method in another project. 
* **CLI**: Is the command line interface jar. This is the JAR you can download to run Crawljax from a command line.
* **Examples**: Some examples on using Crawljax
* **test-utils**: A jar that can be imported in plugins to further test Crawljax. Within this repository, it functions as an integration test.

# Advantages of the new layout:
* Makes the separate repo's for test-utils and parent unnecessary
* cleans up a lot of pom configuration code
* clear separation of concerns in separate modules. 
* Allows for easy module-based extension of the core, like building a web interface.
* Factoring out the CLI modules allows for a nice clean-up in the core code. I think got it fixed now that the CLI package uploads a zip distro to maven central. This means we don't have to host the zip files on our website anymore! Awesome...

## Why do you see 37+ commits in the diff?
Because I submerged the other repositories in here, so you see their history too.

## What needs to be done after/if this is merged?
* Delete the old repos
* Delete the travis builds
* Re-import the project in Eclipse. Eclipse always gets a bit jumpy when you do this type of refactoring.
* Update documentation
* Make a test release to test if the assembly in the CLI module works.