Updates version to Mark 0.7.5
Updates SPStorageObserver protocol
Updates SPStorageProvider protocol
Updates SPStorageObserverAdapter
Implements protocol changes
Wires new SPStorageObserverAdapter callbacks
Implements new SPCoreDataStorage Unit Test
Merge pull request #405 from Simperium/issue/401-fixes-empty-ghost-issue

Issue/401 fixes empty ghost issue
Merge pull request #410 from Simperium/develop

Simperium Mark 0.7.5