Remove encrypt_buffer and decrypt_buffer functions from API

The `encrypt_buffer` and `decrypt_buffer` functions use the `rustc_serialize::from_hex` function, but it is not constant time and leads to secret dependent control flow. These functions shouldn't have been in the API in the first place, and are removed.

Author: raoulstrackx

Cargo.lock

@@ -30,7 +30,6 @@ members = [
     "rs-libc",
     "em-app",
     "em-app/examples/get-certificate/",
-    "em-app/examples/harmonize/",
 ]
 exclude = ["examples"]
 

Cargo.toml

@@ -3,7 +3,6 @@
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-#[macro_use]
 pub extern crate serde_derive;
 
 pub mod mbedtls_hyper;