Trezor One MPMA support

[Skept0x]

Adding MPMA support for Trezor One (The third most important function for hardware wallets after send and sweep).
Currently, Trezor One users are forced to either send assets one by one, or sweep them all.

Prompt after attempting an MPMA using Trezor One:
"Checking data encoding fees on send..."

[B0BSmiths]

I have found the signing of the second TX in a multisend is problematic on Trezor. The Trezor sees the OP return but it ignores the PS2H encoded inputs. It then consumes and an entire UTXO on mining fees as there is no change in the TX and broadcasts the op return without signing the P2SH encoded inputs, so an unrelated entire utxo is consumed and your multisend fails

[jdogresorg]

similar issue as #152