Minor GameContainer changes.

Added copy of GameContainer.java:
- updateAndRender() no longer calls Log.error(), and re-throws the original exception as a SlickException.  This prevents errors from being logged twice, and now the relevant one is shown in the error popup (instead of a useless "failure" message).
- getBuildVersion() no longer calls Log.error(), and removed slick build information from "version" file.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

res/version

@@ -1,6 +1,2 @@
-# opsu! build info
 version=${pom.version}
 build.date=${timestamp}
-
-# slick build
-build=237