Support for ETC/etchash

[gabrielseibel1]

Since moneroocean pool now supports ETC, can the meta-miner support it too? I'm available to help as a volunteer.

[gabrielseibel1]

Aug 04 14:43:20 pop-os mm.js[1356]: 14:43:20 Connected to localhost:3334 [127.0.0.1]
Aug 04 14:43:20 pop-os mm.js[1356]: 14:43:20 Subscribed to Stratum Server
Aug 04 14:43:20 pop-os mm.js[1356]: 14:43:20 Set Extra Nonce: 00
Aug 04 14:43:20 pop-os mm.js[1356]: 14:43:20 Authorized on Stratum Server
Aug 04 14:44:20 pop-os mm.js[1356]: !!! Can't write miner reply to the pool since its socket is closed

It can't benchmark ETC. I guess some coding is needed to run the first job (as with ETH) but IDK the correct parameters to use. If you edit mm.json such that mm.js thinks benchmarking is done, then it mines fine (after adding the coin as an option in mm.js).