Made DBPermissionManager rolesWereChanged() and personaWasChanged() slightly more efficient.
Added changedSince() to DBObjectBaseField
Made DBLog and GanymedeBuilderTask use changedSince()

This saves a trivial Date creation in DBObjectBase.getTimeStamp() and
DBObjectBaseField.getTimeStamp()
Merge branch 'master' into stable

Added changedSince() to DBObjectBase and DBObjectBaseField
Made gasharl custom code use DBObjectBase.changedSince()
Minor javadoc corrections in DBPermissionManager
Fixed up the method javadoc for DBPermissionManager.updatePerms()
Merge branch 'master' into stable

Fixed up various code comments pertaining to recent changes in
permissions handling