Implemented loading Settings from file. Implemented mining of Keystore (key pair). Changed Transaction structure a lot. Added an icon to windows build. Changed some HTML.

src/utils.rs

@@ -1,5 +1,7 @@
 use std::num;
 use rand::Rng;
+use num_bigint::BigUint;
+use num_traits::One;
 
 /// Convert bytes array to HEX format
 pub fn to_hex(buf: &[u8]) -> String {
@@ -33,12 +35,19 @@ pub fn same_hash(left: &[u8], right: &[u8]) -> bool {
     true
 }
 
+pub fn hash_is_good(hash: &[u8], difficulty: usize) -> bool {
+    let target = BigUint::one() << ((hash.len() << 3) - difficulty);
+    let hash_int = BigUint::from_bytes_be(&hash);
+
+    return hash_int < target;
+}
+
 /// Generates random string of given length
 pub fn random_string(length: usize) -> String {
     let chars: Vec<char> = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!?".chars().collect();
     let mut rng = rand::thread_rng();
     let mut result = String::with_capacity(length);
-    for x in 0..length {
+    for _ in 0..length {
         let position: usize = rng.gen::<usize>() % chars.len();
         let c: char = *chars.get(position).unwrap();
         result.push(c);