adding new ObjectManager methods for building RKObjectRequestOperation objects that take an array of response descriptors.  Updated appropriateObjectRequestOperationWithObject:method:path:parameters: to pass only the response descriptors that match the object, path, and method passed in.
Added support for seed databases using WAL
Fixed code styling
Merge pull request #1619 from Neonkoala/development

Added support for seed databases using WAL
Add support for testing mappings with a `nil` source key path. fixes #1582
Fix mapping test breakage
Fix issue where deletion predicate cleanup could evaluate before connections have been established, causing inappropriate object deletion. fixes #1607
Default tests to running with silent logs
Fix test breakage under iOS 7
Bump version to 0.21.0
Merge branch 'release/0.21.0' into development
Do not attempt to continue property mapping skipping logic in the event there is a `nil` value on the property being mapped.
Merge pull request #1526 from jonnolen/limit_operation_responseDescriptors_to_only_relevant_descriptors

Create RKObjectRequestOperations with relevant ResponseDescriptors only
Cleanup unused function warnings when building without Core Data
Bump RKValueTransformers submodule reference
Update projects to Xcode 5 recommended settings
Fix deprecation warnings and use RKValueTransformer API's for configuring date parsing