Remove throws from getPort

[MasterOdin]

When passing certain invalid option configurations to getPort, the function will throw:

node-portfinder/lib/portfinder.js

Lines 136 to 144 in 724a0e1

	if(!options.startPort) {
	options.startPort = Number(options.port);
	if(options.startPort < 0) {
	throw Error('Provided options.startPort(' + options.startPort + ') is less than 0, which are cannot be bound.');
	}
	if(options.stopPort < options.startPort) {
	throw Error('Provided options.stopPort(' + options.stopPort + 'is less than options.startPort (' + options.startPort + ')');
	}
	}

Given the callback nature of usage, I think it'd make more sense to just return an error on the callback vs throwing an error.

[eriktrom]

yep agree