Fix so that raven-sentry compiles on JDK-6.
Merge pull request #75 from buckett/jdk-6

Fix so that raven-sentry compiles on JDK-6.
Don't NPE when closing a badly setup appender.

Log4J can have its configuration reloaded, if the appender wasn't setup
correctly then log4j will attempt to close the appender and this NPEs.

Same thing goes with JUL
Check that we don't close multiple times.
Use a different log setting for unit or integration tests
Update libraries and dependencies
Add test for simple messages in log4j
Move logging.properties to logging-integration.properties

Every other logging system uses a *-integration file for integration
test, follow the same convention with JUL
Use a different log4j.properties file for integration and unit tests
Introduce testng and JMockit as dependencies
Add new tests using testNG in raven-log4j
Nake the injectable mockLogger accessible through the entire test
Add unit test to ensure log levels are indeed converted
Add test to ensure that Exceptions are properly logged
Add test to ensure that MDC details from log4j are added as extra
Add test to ensure that the NDC values are sent as extra
Fix typo
Add test to ensure the source is used as Stacktrace if available
Ensure that the culprit is set to the locationInfo if available
Ensure that the logger name is used as culprit if there is no locationInfo