Fixed a crap tonne of bugs, added some basic thread safety and now you cannot add a player to the database if they're already in it.  Also, now with 100% more SQL injection safety via prepared statements.  A few javadoc comments added.

From this point on (version 0.2), make sure to synchronize on the connectionLock before accessing the connection member.
Removed unused imports.
Added database connector test to FootballPool.doTest().