doc: move dual anchor with escapes to Appendix B.

Draft 0.2; we use a single-sided anchor now, for simplicity.

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

doc/bitcoin.bib

@@ -62,3 +62,8 @@
 	urldate = {2015-07-14},
 	file = {Alt chains and atomic transfers:/home/rusty/.mozilla/firefox/vfn6if9k.default/zotero/storage/PEHK469N/index.html:text/html}
 }
+@misc{go1111111_single_anchor,
+	title = {Idea to improve Lightning Network},
+	urldate = {2015-07-24},
+	note = {\url{https://bitcointalk.org/index.php?topic=1134319.msg11963141#msg11963141}}
+}