mavenized

I completely mavenized the project and split it up in sub modules:

+ yadrone-core contains the base classes needed by all other projects
+ yadrone-controlcenter is the UI to fly the drone. This also creates a fat jar that can be started as {{java -jar yadrone-controlcenter-0.3.1-with-dependencies.jar
+ yadrone-paperchase
+ yadrone-tutorial
+ yardrone-android. This compiles without problems I does however compile against a very old version of android. Usually the min-sdk points to the lowest level of android supported and the target-sdk points to the latest sdk available (android L or 20) in this case.