Merge pull request #2 from leoru/master

add excluded properties mapping
Re: issue #2 - Add documentation for excluded properties
Merge pull request #3 from leoru/master

update cocoapods spec
Merge pull request #4 from leoru/master

add mapping protocol to objects
Refactor RMMapping to include rm_excludedProperties, refactor mutableDictionaryForObject: to use rm_dataKeysForClassProperties
Refactor code for checking basic class type
Update doc for rm_dataKeysForClassProperties
Update doc
Update pod
add inheritance to getting properties for class