clightning: 0.6.0 -> 0.6.1

Update to the latest release.

Highlights for c-lightning users
--------------------------------

  - Less stuck payments: Liveness ping test before locking up funds with peers.
  - Better routing: now considers size of channels.
  - Fewer spurious closes: fee estimate improvements, and new feerates command
  - Several annoying bugs fixed.

Highlights for the network
--------------------------

  - Gossipd now less spammy with channel_update.
  - option_data_loss_protect to protect peers against being out-of-date.
  - Payment errors now refer to the correct channel.

Internal Improvements
---------------------

  - Simplified client flow; after init message exchange by connectd, each is
    isolated in its own daemon.
  - JSON parameter handling vastly simplfied.
  - Python testing framework now uses proper fixtures, and split into separate
    files.
  - Many other cleanups and clarifications.
  - We keepachangelog.com!

Signed-off-by: William Casarin <jb55@jb55.com>