Modify @Condition for detecting existing message bundle resource

The problem with the old code is that it worces a ResourceBundle to
initialize with the default encoding (and that is then cached in the
JDK) during @Condition evaluation (so before the encoding is known).

Includes test for swedish messages

Fixes gh-1228
Ensure embedded containers actually stop if there is an error on startup

Both embedded containers need to be checked after starting to ensure that they
are actually running. With Jetty it's just a question of catching an exception
but with Tomcat it's harder (the current solution involves duplicating some
code from initialize() into start() essentially checking the lifecycle state).

Also adjusted the log levels to prevent noise at WARN level by default when
this happens (since the exception is logged and rethrown anyway).

There is still the issue of whether to fail the build in Maven or Gradle
(separate issue really).

Fixes gh-1232
Dependencies for json-path in BOM
Fix LoggingApplicationListener

- If `logging.config` is set and could open/read the resource
then, return.
  - Currently, it logs warning though the resource is successfully
read.
Upgrade to Groovy 2.3.4

Closes #1224
Upgrade to HikariCP 1.4.0

Closes #1220
Add dependency management for spock-spring and document its use

Closes #1234
MvnLauncher (v1)