Pool server for equihash solution <n, k>

[litecoinz-project]

This PR, together with those to be applied on equihashverify and node-stratum-poo, allows to install a pool server based on z-nomp able to manage and validate the following equihash solutions:

• n = 48, k = 5
• n = 96, k = 3
• n = 96, k = 5
• n = 192, k = 7
• n = 200, k = 9

Supported equihash algorithm options:

• Equihash48_5
• Equihash96_3
• Equihash96_5
• Equihash144_5
• Equihash192_7
• Equihash200_9

Dependencies:
HorizenOfficial/equihashverify#2
z-classic/node-stratum-pool#35

[tarrenj]

Concept ACK, also see https://github.com/NickRHill/zh-nomp

[litecoinz-project]

They accept only equihash as coin algorithm parameter. That implementation precludes the use of z-nomp in a generic way for all the variants of equihash (n = 200 / k = 9, n = 144 / k = 5, n = 192 / k = 7, etc etc) because these parameters are hard-coded in their equihashverify fork and not passed as in my implementation from z-nomp coin configuration:

z-nomp -> node-stratum-pool -> equihashverify 

[litecoinz-project]

See also PR HorizenOfficial/node-stratum-pool#1

[tarrenj]

We're not maintaining this anymore, you'll have much better success over at the S-NOMP repo: https://github.com/s-nomp I think they've already implemented this though.