v1.8.1

This release includes the following features:

• Implementation of Liveliness QoS

It also adds the following bug fixes and improvements:

• Fix for get_change on history, which was causing issues during discovery
• Fix for announcement of participant state, which was sending ParticipantBuiltinData twice
• Fix for closing multicast UDP channel
• Fix for race conditions in SubscriberHistory, UDPTransportInterface and StatefulReader
• Fix for lroundl error on Windows in Time_t
• CDR & IDL submodules update
• Use of java 1.8 or greater for fastrtpsgen.jar generation