Upgrade elastic-array to 0.9.0

This is a huge change, which includes some changes to replace code that
originally cloned to reuse allocations instead. The updated
`elastic-array` crate renames its consuming `Vec`-conversion method to
`into_vec`, which means that I can do a simple
`sed -i 's/to_vec/into_vec/'` and then fix the compilation errors.

This commit is probably a minor performance win and definitely a
significant readability win.

ethstore/src/account/crypto.rs

@@ -104,7 +104,7 @@ impl Crypto {
 			cipher: Cipher::Aes128Ctr(Aes128Ctr {
 				iv: iv,
 			}),
-			ciphertext: (*ciphertext).to_vec(),
+			ciphertext: ciphertext.into_vec(),
 			kdf: Kdf::Pbkdf2(Pbkdf2 {
 				dklen: crypto::KEY_LENGTH as u32,
 				salt: salt,