Added network class (isOnline, isWifiConnected, isMobileConnected)

[cbrhex]

Added network class with methods:

• isOnline - check internet connection

• isWifiConnected - check wifi connection

• isMobileConnected - check mobile connection

This way you can check internet connection before a sign in happens

func gpgs_sign_in():
    gpgs.init(get_instance_ID())

    if gpgs.isOnline():
        gpgs.signIn()

[jlopezcur]

Thanks @Cyber-host !