Issue40 fix crush

[biggieman]

#40 I think only one place need fix.

[Jexordexan]

Thanks for fixing this! I noticed there are other places that may throw an error on a bad choice selection. Namely this.label() and this.encode()
I'm aware that the developer can override these methods and put in their own null checks, but I believe they should work by default. I've fixed mine by just putting choice && before the return value. A simple short circuit does the trick!

EDIT: Disregard this comment, I've tested your changes and they seem to have fixed the problems I had mentioned as well. Thanks Again @biggieman

[ProLoser]

Is there a reason for this change?

[biggieman]

Yes, it's not necessary for example, but on original gulpfile.js task scripts:example pipes ngAnnotate (like main scripts)

[ProLoser]

I don't think the modification to the example file is necessary. If you remove it I'll merge in this change.

[ProLoser]

Along with #35 I prefer NOT to use the more explicit injection syntax because that should be handled by a preprocessor so that the source code can be minimal. Additionally, the minified version of the example does NOT rename the variable, voiding the need for this injection syntax. Finally, there's no reason for anyone to re-process the example file itself since it's only an example.

[biggieman]

@ProLoser: remove annotates from this pull and #35
@Jexordexan this functions used at ngModel rendering and we breaks render in this.select().