Fix #85 - Don't serialize properties in a search that weren't explicitly set by the user.
- Normalize object serialization so not duplicated between NSObject+JSON/buildUpdateDictionary
- Extend the "dirty" serialization to BuddyObjects + SearchObjects
Ensure new dirty-based serialization works for properties up the class hierarchy.
Merge pull request #90 from BuddyPlatform/FilteredSearch

Fix #85 - Don't serialize properties in a search that weren't explicitly...