Update token example with mint and transfer

examples/token/src/main.leo

@@ -10,3 +10,26 @@ record Token {
 function main(t: Token) -> u64 {
 	return t.amount + t.amount;
 }
+
+function mint(owner: address, amount: u64) -> Token {
+    return Token {
+        owner: owner,
+        gates: 0u64,
+        amount: amount,
+    };
+}
+
+function transfer(token: Token, to: address, amount: u64) -> (Token, Token) {
+    let difference: u64 = token.amount - amount;
+    let remaining: Token = Token {
+        owner: token.owner,
+        gates: token.gates,
+        amount: difference,
+    };
+    let transferred: Token = Token {
+        owner: to,
+        gates: 0u64,
+        amount: amount,
+    };
+    return (remaining, transferred);
+}