Update NEWS.md with all changes since v2.3.0 so far.
Update NEWS.md with all changes since v2.3.0 so far.

sourcefrog/librsync,sourcefrog/librsync,sourcefrog/librsync,sourcefrog/librsync,dbaarda/librsync,librsync/librsync,librsync/librsync,dbaarda/librsync,librsync/librsync,dbaarda/librsync,librsync/librsync,dbaarda/librsync