[CDF-431] Centralize MessageBundlesHelper calls: move class to cpf-core
	- added minor validation: check if a messages.properties was properly created/stored in cache dir; in the off-chance there isn't one, go ahead and create an empty one there
Merge pull request #50 from pedrofvteixeira/CDF-431

[CDF-431] Centralize MessageBundlesHelper calls: move class to cpf-core