i07t05: Coral workers implementation

There have been added handshake, sign_in, sign_out
and get_feed_list to Coral. #130
i07t05: Coral workers implementation

There has been added createFeed to Coral. #130
i07t06: Introduction of Memcached in both Coral and Lionfish

There has been added cache worker system to Coral, which is responsible
for supporting Memcached. #131