DeviceMgr.scan_devices: do all scanning on hidapi thread
DeviceMgr.scan_devices: do all scanning on hidapi thread

e.g. the trezor custom enumerate function calls hid.enumerate() which is not thread safe (?).
see comment on line 330

pooler/electrum-ltc,wakiyamap/electrum-mona,pooler/electrum-ltc,wakiyamap/electrum-mona,spesmilo/electrum,wakiyamap/electrum-mona,pooler/electrum-ltc,spesmilo/electrum,wakiyamap/electrum-mona,spesmilo/electrum,pooler/electrum-ltc,spesmilo/electrum