Browserstack support

[yuriy-yarosh]

Could you please add some BrowserStack support ?

func BrowserStack(name, platform, browser, version, username, accessKey string, options ...agouti.Option) (*agouti.Page, error) {
	url := fmt.Sprintf("http://%s:%s@hub-cloud.browserstack.com//wd/hub", username, accessKey)
	capabilities := agouti.NewCapabilities().Browser(browser).Platform(platform).Version(version)
	capabilities["name"] = name
	return agouti.NewPage(url, append([]agouti.Option{agouti.Desired(capabilities)}, options...)...)
}

Too busy and a bit lazy to PR this.

[excavador]

Any updates?

[yuriy-yarosh]

@excavador I could make a PR later today.

[excavador]

@yuriy-yarosh it would be awesome! Thank you!