Merge pull request #1 from basitali/master

Ability to fill existing object with new data from an NSDictionary.
Update README.md
Update README.md
Merge pull request #2 from basitali/master

EKSerialize should use fieldMapping.keyPath instead of fieldMapping.field so that mapper and serializer work together.
preparing for 0.2.1 version
Add managed object mapper for CoreData object mapping
Add CoreData section to README
Don't create empty managed objects

For managed objects if there is an empty representation it would create
an empty managed object, which would make validations fail. Now if the
representation is empty no object is created.
Convert NSNull values to nil
Reorganize sources, add CoreData example project and tests
Fix problem with Pods config for the test target
Merge pull request #4 from aleph7/core_data

Support for managed objects
Update README.md
Update README.md
Update README.md
Update README.md
removing EKManagedObjectMapper and adding its methods to reuse some methods of the EKMapper
preparing for the next version
Update README.md
adding coredata to podspec