Updated style in MTLManagedObjectAdapterSpec.m
Fixed implicit nil comparison in MTLManagedObjectAdapter.m
Removed unnecessary NSUnderlyingErrorKey
Updated other style errors in MTLManagedObjectAdapterSpec.m
Merge pull request #2 from akashivskyy/master

Fixed style errors in MTLManagedObjectAdapter.m and MTLManagedObjectAdapterSpec.m