Merge pull request #3 from vokal-isaac/master

Update to match 1.0.0 changes to VOKCoreDataManager
updated submodule
added ignoreNullValueOverwrites to mapper
updated core files
fixed spelling
Merge pull request #4 from seanwolter/master

tests for ignoreNullValueOverwrites and update to submodule
updated core files
updated submodule
updated core files
updated core files
fixed submodule again
updated core files
objective clean fixes
updated core files
updated core files
updated core files
updated core files
updated core files
added post import and post export blocks to VOKManagedObjectMapper
project file and core files updated