Sandbox integration

First part of sandbox integration with gameplay/board/bots services.

Changed GamePlay interface a bit - now it returns UUID of created game. UUID is created during game creation so there is no need now to wait until InMemoryGameHistory assigns id after finished game. Thanks to this it was possible to remove AtomicInteger from mentioned class.

I had to change most of the ids present in the gameplay/engine code from int/Integer -> String because bot service returns bot ids in String form and there were dependency between botId <-> tankId. We should probably have a little discussion about all different ids and who is responsible for what. 

There are some commits with pom cleanup - moved some depndencies to parent pom. 

All the tests apart from one are passing (and this test was not passing before I changed anything) so everything should work fine - during smoke test execution I can see some bot movement so it seems that it is working.
I moved the dependencies to the parent pom but still in this situation you need to specify at least groupId and artifactId of the dependency in children project if you want to use the dependency there. 

http://stackoverflow.com/questions/13894701/maven-3-dependencies-from-parent-pom-not-available-to-children-in-eclipse
http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Management
http://books.sonatype.com/mvnref-book/reference/pom-relationships-sect-project-dependencies.html#pom-relationships-sect-dep-manage