Note that check-whitespace and check-bolt already do this, so we
can eliminate redundant lines in common/Makefile and bitcoin/Makefile.
We also include the plugin headers in ALL_C_HEADERS so they get
checked.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fixes: #2679
Changelog-Added: JSON-RPC: New `multiwithdraw` command to batch multiple onchain sends in a single transaction. Note it shuffles inputs and outputs, does not use BIP69.