hdwallet-metamask's partial multi-account support uses a definitely-wrong derivation path

[mrnerdhair]

While hdwallet-metamask does not fully support multiple accounts, its ethGetAccountPaths and describePath functions do, and assume the standard BIP44 derivation scheme (m/44'/60'/n'/0/0) even though MetaMask itself uses m/44'/60'/0'/0/n (unless it's being used with a hardware wallet, in which case all bets are off).

Options:

• Update hdwallet-metamask to use Metamask's native account derivation scheme in these functions instead of BIP44. (This isn't perfect, but at least it won't be clearly wrong anymore.) (This is the approach taken by metamask: use metamask-style account path derivation #424.)
• Return [] (or throw) from ethGetAccountPaths and throw in describePath to avoid exposing wrong functionality.
• Support multiple accounts in MM "properly" somehow.