Fix changing countries when you have a string like "+1.3451234567"

You can reproduce the bug by doing the following:

1. Go to the [demo page](http://jackocnr.com/intl-tel-input.html)
2. Paste this phone number into the box: `+1.3451234567`
3. Notice that the flag correctly updates to show Cayman Islands as the country
4. Click on the flag and change the country to something else, like Cameroon (+237)

Expected Result:
- Phone number should change to `+237 1234567`

Actual Result:
- Phone number does not change

This only affects countries with four-digit dialing codes.  In reality, I think these are country code 1 and these small countries have an area code assigned to them.. but that's another discussion.