FC-69 Update to Spring 4; Fix for @Retryable exception handlers

This is a fix to enable exception handlers referenced by @Retryable methods to use annotated features, such as @Transactional and @ContinueResult. This required an upgrade from Spring 3 to 4, to enable proxying of classes (rather than just interfaces).

Signed-off-by: Steffan Westcott <steffan.westcott@clicktravel.com>