Feature/gemify

Wraps this project in a gem which creates rake tasks for starting and stopping Marmotta.  For now, these tasks can be used as instructed `README.md`.  

In the longer term, they are meant to be included in another project's tasks, to create a project specific environment.  That will require a task to download either the marmotta files (and unzip them) or a runnable `jar`.  It probably would also benefit from project specific configuration (especially the port used by Tomcat).

Also adds (possibly temporarily) a vagrant environment for more reliable spin-up.