Need to remove 'typeof' type checking

[gear54rus]

And use util.* functions for consistency:

runtime/endpoint.js:57:          if (typeof v1 === 'string' && v1.length > 0) {
runtime/endpoint.js:254:          if (typeof result.exports !== 'function')
runtime/instance.js:365:    if (typeof constructor !== 'function') {
runtime/instance.js:394:          if (typeof resource.provision === 'function') {
runtime/instance.js:405:            if (typeof result.then === 'function') {
runtime/instance.js:461:          if (typeof resource.configure === 'function') {
runtime/instance.js:472:            if (typeof result.then === 'function') {
runtime/instance.js:518:        if (typeof resource.unprovision === 'function') {
runtime/instance.js:529:          if (typeof result.then === 'function') {
runtime/router.js:331:            if ((typeof virtualHost === 'string') && (virtualHost.split(':')[0] === endpoint.virtualHost))
runtime/service.js:41:    if (typeof code !== 'string')
util/logger.js:23:    if ((typeof path !== 'string') || !path)
util/util.js:17:    return (typeof arg === 'string') && (arg.length > 0);
util/util.js:82:    if (typeof obj === 'string') obj = {