Need to add new transaction types to GetTransactions

[mDuo13]

Only 8 transaction/pseudo-transaction types are recognized by the GetTransactions method:

https://github.com/ripple/rippled-historical-database/blob/develop/api/routes/getTransactions.js#L8-L17

However, amendments have added the following 7 additional transaction types:

• EscrowCreate
• EscrowCancel
• EscrowFinish
• PaymentChannelCreate
• PaymentChannelClaim
• PaymentChannelFund
• SignerListSet

EDIT: Very soon, amendments will add the following additional transaction types:

• CheckCreate
• CheckCash
• CheckCancel

Also, there are 2 new tec codes that can appear as transaction results:

• tecINVARIANT_FAILED
• tecEXPIRED