Incorrect thumb joints nomenclature

[andreh1111]

Hi, I think the myoHand nomenclature related to the thumb joints (cmc_abduction, cmc_flexion, mp_flexion, ip_flexion) isn't correct for two reasons:

1. for all the other fingers, the word after "_" is what happens toward the maximum value of qpos (e.g., when mcp2_flexion is max, the index finger is flexed) while the thumb joints are extended when _flexion is max. The same logic is for _abduction.
2. cmc_abduction and cmc_flexion are reversed.

[Vittorio-Caggiano]

Hi @andreh1111 thanks for pointing to this issue. We will update the hand model after the MyoChallenge.