toBuffer does not accept hex? about ethereumjs-util

[fanatid]

add 0x to private key...
and check source code

ethereumjs-util/index.js

Lines 153 to 175 in 926f2d7

	exports.toBuffer = function (v) {
	if (!Buffer.isBuffer(v)) {
	if (Array.isArray(v)) {
	v = Buffer.from(v)
	} else if (typeof v === 'string') {
	if (exports.isHexString(v)) {
	v = Buffer.from(exports.padToEven(exports.stripHexPrefix(v)), 'hex')
	} else {
	v = Buffer.from(v)
	}
	} else if (typeof v === 'number') {
	v = exports.intToBuffer(v)
	} else if (v === null || v === undefined) {
	v = Buffer.allocUnsafe(0)
	} else if (v.toArray) {
	// converts a BN to a Buffer
	v = Buffer.from(v.toArray())
	} else {
	throw new Error('invalid type')
	}
	}
	return v
	}