Filter fixes
OPAL-2124: Adding listener for project delete to update registrations...
Display database name when displaying connection successfull
OPAL-2121: Validate database connection before saving a project
Invalidate database cache when saving if there is no datasource associated
OPAL-2124: Fixing ConcurrentModificationException
Split success and fail callbacks
TO is translatable
Using @NotNull instead of @Nonnull
Merge pull request #351 from emorency/master

Database improvements and bug fixes