Shellscript for automatic updating

[ceruzaa]

To make it quicker and easier to get the latest features of Dave, a shell script should be provided by the repository that does the following things when executed:

1. Check if the current version is the latest version; if it is, continue:
2. Clone the repository
3. Unzip the cloned files
4. Use maven to build a new Jar
5. Shut down the current version of Dave
6. Replace JAR
7. Start the new Jar.

This will also require Dave to store it's PID in a file on startup.