Fixed Game Over bugs.

-Removed ability to start new round after game over.
-fixed bug where zombies would try to find their target but no target
exists.
Barriers no longer spawn in player spawn.
Removed bug where other non-owner of the Tower could control it
throws exception due to change in the p2pHub (server and client) classes.
They now throw an exception if connection fails.
added intro pop-up boxes so players can easily choose solo, multiplayer and who to connect to
added Eclipse project files to .gitignore