Cuckoo-miner better merged into Grin (#80)

* Adding cuckoo-miner into grin as a proper dependency now
* Defaulting to using cuckoo-miner
* Updates to tests to use cuckoo_miner by default, (using cuckoo16)

config/src/config.rs

@@ -198,9 +198,6 @@ fn test_read_config() {
         burn_reward = false
         #testing value, optional
         #slow_down_in_millis = 30
-        #testing value, should really be removed and read from consensus instead, optional
-        #cuckoo_size = 12
-
 
     "#;