lib/options.js
function(opts) {
		if (opts.preScriptFile) {
			var path = require('path');
			opts.preScript = require(path.resolve(opts.preScriptFile));
			delete opts.preScriptFile;
		}
		opts.preScript = opts.preScript || function(browser) {
			return;
		};
		return opts;
	}
function(opts) {
		if (opts.preScriptFile) {
			var path = require('path');
			opts.preScript = require(path.resolve(opts.preScriptFile));
			delete opts.preScriptFile;
		}
		opts.preScript = opts.preScript || function(browser) {
			return;
		};
		return opts;
	}
preScript, preScriptFile