[WIP] Aggsig Transactions (#530)

* First steps converting transaction workflow to be aggsig-enable

* integrating updated version of aggsig, which gives greater control over the contents of e

* added wallet transaction test to testing framework to enable testing the whole thing, completed interaction as far as inital response from recipient

* more aggsig work, final signature is produced now

* Construction of aggsig transaction now working to the point of the signature being built

* aggsig transactions working end-to-end in the nominal case

* refactor aggsig verify from commit and fix some tests

* more cleanup and test fixing

* cleaning up automated tests

* test+formatting fix

util/src/lib.rs

@@ -25,7 +25,7 @@
 extern crate slog;
 extern crate slog_async;
 extern crate slog_term;
-
+extern crate byteorder;
 extern crate rand;
 
 #[macro_use]
@@ -48,12 +48,13 @@ pub mod secp_static;
 pub use secp_static::static_secp_instance;
 
 pub mod types;
-pub use types::LoggingConfig;
+pub use types::{LoggingConfig, LogLevel};
 
 // other utils
 use std::cell::{Ref, RefCell};
 #[allow(unused_imports)]
 use std::ops::Deref;
+use byteorder::{BigEndian, ByteOrder};
 
 mod hex;
 pub use hex::*;
@@ -98,3 +99,11 @@ impl<T> OneTime<T> {
 		Ref::map(self.inner.borrow(), |o| o.as_ref().unwrap())
 	}
 }
+
+/// Construct msg bytes from tx fee and lock_height
+pub fn kernel_sig_msg(fee: u64, lock_height: u64) -> [u8; 32] {
+	let mut bytes = [0; 32];
+	BigEndian::write_u64(&mut bytes[16..24], fee);
+	BigEndian::write_u64(&mut bytes[24..], lock_height);
+	bytes
+}