implement MessageQueue class
fix to use size_type for ret value
implement Errorable
implement [operator =] in Errorable class
remove explicit in Errorable constructor
refactor Errorable Test
fix to return reference in Errorable Getter
add default constractor & operator in Errorable class
implement MessageQueue#empty()
fix to return error with MessageQueue#recv() if empty
fix to set max queue size in MessageQueue
fix not to send if queue is full
fix type : MessageQueue::size_type
fix to throw std::logic_error with Errorble getter
fix getter like std::exception :Error#get() => Error#what()
fix to add header for exception
add option : pre include files
implement MessageQueue::recv_wait()
implement MessageQueue::send_wait()
fix to use typedefed type in MessageQueue Thread test