Fix: Ycash segwit & add `FLUX` and `YEC` on cryptocurrencies docs.

Bump: Python-HDWallet from `v2.1.2` to `v2.2.0` package.

Merge pull request #69 from pjkundert/fix-keccak

Update from pysha3 (deprecated) to pycryptodome for Keccak-256

Bump: Python-HDWallet from v2.1.0 to v2.1.1 package.

Bump: Python-HDWallet from v2.0.1 to v2.1.0 package.

Bump: HDWallet from v2.0.0 to v2.0.1 package.

Bump: HDWallet from v1.3.2 to v2.0.0 package.

Bump: HDWallet from v1.3.1 to v1.3.2 package.

Update: Testing doc and added development doc.

Update: Testing doc and added development doc.