Allow unconditional TestLockerManager breakpoint

Moving exception throw directive to a separate line from the
conditional enclosing it to make debugging that line less annoying
Merge branch 'config' of github.com:thinkaurelius/titan into config
Run TitanEventualGraphTest serially

Annotated the entire class with @Category({ SerialTests.class }).
Some methods were annotated this way before, but not the whole class.
I couldn't immediately tell whether the non-serial methods could
trigger conflicting concurrent writes to the public static variable
TestLockerManager.ERROR_ON_LOCKING, and the cost of making the whole
thing serial was negligible, so I did.
Adding embedded Cassandra @BeforeClass methods

These aren't necessary in most cases, but they are useful when test
would otherwise start, shutdown, and restart short-lived
embeddedcassandra graphdb instances in a single forked test VM; the
embedded Cassandra starter does not react well when asked to restart
after the first shutdown