Add Flux Cryptocurrency, fix prefix naming error

[MorningLightMountain713]

Adds support for Flux.

Also fixed up the typo that had the "MESSAGE_PREFIX" as "MASSAGE_PREFIX" for a lot of the currencies.

chain params found here:

https://github.com/RunOnFlux/fluxd/blob/master/src/chainparams.cpp

I have tested this locally and valid addresses are generated.

Snip from from_mnemonic.py example using Flux cryptocurrency:

Finger Print: 66052008
Semantic: p2pkh
Path: m/44'/19167'/0'/0/0
Hash: 66052008514f49939b9e2cdb1efcd7e210f4c978
P2PKH Address: t1TB35168bZaoAQh2VPrdyPS6uNw7E1oyjq
P2SH Address: t3X1Ren7FzT3eCuWv4Skz6jbsyByDs93Eje
P2WPKH Address: None
P2WPKH In P2SH Address: None
P2WSH Address: None

Here is the address validated:

mmf@seahorse:~$ flux-cli validateaddress t1TB35168bZaoAQh2VPrdyPS6uNw7E1oyjq
{
  "isvalid": true,
  "address": "t1TB35168bZaoAQh2VPrdyPS6uNw7E1oyjq",
  "scriptPubKey": "76a91466052008514f49939b9e2cdb1efcd7e210f4c97888ac",
  "ismine": false,
  "iswatchonly": false,
  "isscript": false
}

[meherett]

@MorningLightMountain713 Nice work, please add Flux cryptocurrency into https://github.com/meherett/python-hdwallet#available-cryptocurrencies.

[MorningLightMountain713]

@MorningLightMountain713 Nice work, please add Flux cryptocurrency into https://github.com/meherett/python-hdwallet#available-cryptocurrencies.

Done