Create class for common synced settings
Add SyncSettingItem in Account and remove common variables
Add SyncSettingItem in DropServer and remove common variables
Add SyncSettingItem in Identity and remove common variables
Add SyncSettingItem in StorageServer and remove common variables
Add SyncSettingItem in StorageVolume and remove common variables
Update test
Add documentation
Changed data types to be basic w/ default values

Update hashCode() and equals() method accordingly.
Merge pull request #177 from k-c13:setting-timestamp

fix #176 updated, created and deleted have to be a long not an integer