Correct way to add Equihash 192,7 support. 
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### Description

I am currently trying to add support for Vidulum (Equihash 192,7) From what I could gather, Equihash 96,5 144,5 and 209,9 are supported. What is the correct way to add 192,7? I have tried editing EquihashSolver.cs to allow 192,7 but when I try to re-build it throws this error: Crypto/Hashing/Equihash/EquihashSolver.cs(135,45): error CS0117: 'LibMultihash' does not contain a definition for 'equihash_verify_192_7' [/home/pool/miningcore/src/Miningcore/Miningcore.csproj]

I have since tried to look inside Miningcore.csproj file and cannot find anything relevant to equihash there.

### Steps to Reproduce
1. Add changes to EquihashSolver.cs
2. Rebuild using guide on Github
3. Error is produced.

### Expected behavior

Compile complete

### Actual behavior

Error's out. 

### Reproduces how often

100%

### Version

If you are using released version, please state your version.
If you are using clone from `dev` branch, please state commit hash of your copy.
Also, please include the OS name and version you're currently running.

I am running the latest version of MiningCore and have done some adjustments to the back end to allow Lyra2v3 and x21s. I am running Ubuntu Server 16,04 LTS

### Additional Information

Any additional information, log, configuration or data that might be necessary to reproduce the issue.
