Support Dual Mining Options

[MaynardMiner]

Nicehash added kHeavyHash, which makes dual mining options possible. SWARM needs to add support for dual mining.

-Add dual mining combinations like separate algos.
-Create a method to distinguish which oc to use for dual mining through HiveOS API.
-Expand upon HiveOS api to support dual mining statistics (If Possible) through custom miner API.

[MaynardMiner]

This will also require a change in the statistics system to combine two prices together to get a total estimate based on benchmarks for dual mining setup.

[MaynardMiner]

Also needs a method to add/remove dual mining combinations using -Algorithm