selectAccount
Selects a specific account in the HD wallet hierarchy.
Derives to path: m/44'/2400'/account'
BIP-44 Account Semantics:
Account 0: Default account for most users
Account 1+: Additional accounts for organization/privacy
Return
HDWalletAccount for further derivation
Parameters
account
Account index (typically 0)
Throws
if wallet has been cleared
if account is negative