v0.4.3

It's been a while. This release adds:

• Path presets for common wallet software, hardware wallets, and Bip standards such as Bip32, Bip44, Bip49, Bip84.
• Variables in paths for insertion of coin, account, and change values.
• Iteration can now occur at any path level, not only the deepest level. (needed by Ledger-Live)
• added --gen-words flag to control how many mnemonic words are created. [12..48]
• corrected ethereum private key serialization
• minor bug fixes