added initial version of MicrosliceContainer: combines microslice descriptor and payload to offer a cleaner interface to higher-level applications
use {} initialization if possible, added note why () has to be used in a certain case
MicrosliceContainer::content public member is pointer, not vector; the vector is now private
added new constructor for MicrosliceContainer which allows passing a pointer to the payload directly, in this case the private _content vector is unused
moved MicrosliceContainer implementation to cpp file, streamlined comments/doc
added overload of StorableTimeslice::append_microslice which takes a MicrosliceContainer instead of a descriptor and a pointer separately
added include guard
pointer to microslice contents declared const in several places
added Timeslice::get_microslice, which returns a MicrosliceContainer, to offer a cleaner interface for higher-level applications
use consistent wording
Merge pull request #2 from spadic/microslice

extend Timeslice API to simplify passing Microslices around