add methods for checking if specific target message is actioned in an action channel
add AATTActionMessageSpec

contains ids for action and target
add database methods for getting action message specs
pragma mark, dog
add convenience methods for getting ids as NSNumbers
add method for adding display date annotation to messages
add class method for creating an unsent message plus
unsent messages now held in dictionary, cannot fetch new ones when unsent exist
add method for creating unsent message and methods for sending unsent messages