Fix tests broken due to non-deterministic execution order on JDK 7

There are a number of tests that make pretty strong assumptions about execution order, relying on
shared data set up in @BeforeClass that is mutated by other test methods.

There are a couple strategies taken to address this:

1) Update to JUnit 4.11 which introduces the @FixMethodOrder annotation and enforce test execution
   in order sorted on method name (and in some cases make sure the methods sort in lexographically-
   happy order)

2) Update the test methods to reset the state they are testing at the start of execution

Strategy #2 is better, but I didn't push that through all the failing cases
Use the appropriate findbugs dependency at compile time for annotations support.

Depending on the findbugs module pulls in a huge chain of nasty dependencies (asm, xerces, xalan, jaxen) which cause
much grief downstream.

We only need the findbugs annotations module as our compile time dependency for the findbugs exclusions
Add longer sleep for timing sensitive test

I can repro this failed build:
https://netflixoss.ci.cloudbees.com/job/archaius-pull-requests/8/testReport/junit/com.netflix.config.sources/DynamoBackedConfigurationTest/testPropertyChange/

if I set the sleep to 990 millis.  I bumped it up to 1250...
Additional delay for slow build slaves
Merge pull request #114 from cfieber/master

Remove findbugs as a compile time dependency (replace with findbugs annotations)