Get the list of current witnesses.
client.request('get_witnesses', null, function(err, result) {
console.log(result);
});
[
'BVVJ2K7ENPZZ3VYZFWQWK7ISPCATFIW3',
'DJMMI5JYA5BWQYSXDPRZJVLW3UGL3GJS',
'FOPUBEUPBC6YLIQDLKL6EW775BMV7YOH',
'GFK3RDAPQLLNCMQEVGGD2KCPZTLSG3HN',
'H5EZTQE7ABFH27AUDTQFMZIALANK6RBG',
'I2ADHGP4HL6J37NQAD73J7E5SKFIXJOT',
'JEDZYC2HMGDBIDQKG3XSTXUSHMCBK725',
'JPQKPRI5FMTQRJF4ZZMYZYDQVRD55OTC',
'OYW2XTDKSNKGSEZ27LMGNOPJSYIXHBHC',
'S7N5FE42F6ONPNDQLCF64E2MGFYKQR2I',
'TKT4UESIKTTRALRRLWS4SENSTJX6ODCW',
'UENJPVZ7HVHM6QGVGT6MWOJGGRTUTJXQ'
]
