Merge branch 'release/0.3.3' into develop
[update] attribute mappings shortcut
[rename] FEMExceptable to FEMExcludable
[remove] extra categories
[minor] renaming
[update] assignment policies implementation
[add] collection synchronization
[fix] type
[add] synchronization specs
[podspec] updated 0.3.7
[fix] spec typo
[version] 0.3.7
[remove] error import
Merge branch 'master' into release/0.3.7
[readme] updated
Merge branch 'release/0.3.7'