v0.0.104.0

• Updates to LDK version 0.0.104. See
  https://github.com/lightningdevkit/rust-lightning/releases/tag/v0.0.104
  for the full changelog.
• Use Reference.reachabilityFence to work around Java's somewhat
  poorly documented memory model. This seems to be the intended use so
  its likely this will fix the early finalization bugs we've seen, but
  formal documentation on the Java memory model appears to be lacking
  so its possible (albeit unlikely) that more may be required later.
  This bumps our required Java version from 1.8 to 9.
• Exposes Hash and Eq via Java's hashCode and equals.
• Thows an exception instead of incorrect operation if multiple
  ChannelMonitors for the same channel are provided to a
  ChannelManagerConstructor.