Move bitcoin stuff into bitcoin subdir.

It's not very interesting if you're looking for LN code.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

bitcoin/pubkey.h

@@ -0,0 +1,21 @@
+#ifndef LIGHTNING_BITCOIN_PUBKEY_H
+#define LIGHTNING_BITCOIN_PUBKEY_H
+#include <ccan/short_types/short_types.h>
+#include <ccan/tal/tal.h>
+#include "../lightning.pb-c.h"
+
+struct pubkey {
+	u8 key[65];
+};
+
+/* Convert to-from protobuf to internal representation. */
+BitcoinPubkey *pubkey_to_proto(const tal_t *ctx, const struct pubkey *key);
+bool proto_to_pubkey(const BitcoinPubkey *pb, struct pubkey *key);
+
+/* 33 or 65 bytes? */
+size_t pubkey_len(const struct pubkey *key);
+
+/* Convert from hex string (scriptPubKey from validateaddress) */
+bool pubkey_from_hexstr(const char *str, struct pubkey *key);
+
+#endif /* LIGHTNING_PUBKEY_H */