Detect updated UA for Googlebot (#41)

Updated user agent for Googlebot

The new user agent has Android instead of iPhone. This patch adds the detection by calling the p.googleBot() method accordingly.

all_test.go

@@ -25,10 +25,15 @@ var uastrings = []struct {
 		expected: "Mozilla:5.0 Browser:Googlebot-2.1 Bot:true Mobile:false",
 	},
 	{
-		title:    "GoogleBotSmartphone",
+		title:    "GoogleBotSmartphone (iPhone)",
 		ua:       "Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)",
 		expected: "Mozilla:5.0 Browser:Googlebot-2.1 Bot:true Mobile:true",
 	},
+	{
+		title:    "GoogleBotSmartphone (Android)",
+		ua:       "Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.96 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)",
+		expected: "Mozilla:5.0 Browser:Googlebot-2.1 Bot:true Mobile:true",
+	},
 	{
 		title:    "BingBot",
 		ua:       "Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)",

operating_systems.go

@@ -88,6 +88,8 @@ func webkit(p *UserAgent, comment []string) {
 		}
 		if len(comment) > 3 {
 			p.localization = comment[3]
+		} else if len(comment) == 3 {
+			_ = p.googleBot()
 		}
 	} else if len(comment) > 0 {
 		if len(comment) > 3 {