Initial project setup.

`pom.xml` – Use Maven as build tool.
`.gitignore` – Don't track files that are generated by Maven.
`.editorconfig` – Basic definition of the coding style.
`.travis.yml` – Configuration of the CI server.
Create method that exposes an exception.

This is the core feature of Fishbowl. Example usage:

    Throwable exception = exceptionThrownBy(
         () -> throw new NullPointerException());