Add no_std support to transcript, dalek-ff-group, ed448, ciphersuite, multiexp, schnorr, and monero-generators

transcript, dalek-ff-group, ed449, and ciphersuite are all usable with no_std
alone. The rest additionally require alloc.

Part of #279.

crypto/ed448/src/lib.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
-#![no_std]
 #![doc = include_str!("../README.md")]
+#![no_std]
 
 #[macro_use]
 mod backend;