interface: minor clean-up split out _set_proxy from init
interface: minor clean-up split out _set_proxy from init

fujicoin/electrum-fjc,neocogent/electrum,vialectrum/vialectrum,spesmilo/electrum,pooler/electrum-ltc,pooler/electrum-ltc,pooler/electrum-ltc,wakiyamap/electrum-mona,vialectrum/vialectrum,fujicoin/electrum-fjc,cryptapus/electrum,neocogent/electrum,wakiyamap/electrum-mona,wakiyamap/electrum-mona,vialectrum/vialectrum,cryptapus/electrum,fujicoin/electrum-fjc,wakiyamap/electrum-mona,spesmilo/electrum,cryptapus/electrum,neocogent/electrum,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc