2018-08-10 version 3.1.0

• Improve documents (#687, #718)
• Add fuzzer support (#689)
• Fix msgpack::object union member access bug (#694)
• Improve cross platform configuration (#704)
• Fix out of range dereference bug of EXT (#705)
• Add timestamp support. std::chrono::system_clock::time_point is mapped to TIMESTAMP (#706)
• Add minimal timestamp support for C. The type msgpack_timestamp and the function msgpack_object_to_timestamp() are introduced (#707)
• Improve MSGPACK_DEFINE family name confliction probability (#710)
• Add no static-library build option (BUILD_SHARED_LIBS=ON) (#713, #717, #722)
• Add header only cmake target (#721)
• Add std::byte adaptor (#719)
• Remove some warnings (#720)