Added support for ngModel to be used seemless with isolate scope

[basarat]

Fix for #1924

Added implementation + Updated documentation.

You no longer need to do

<my-component ng-model="$parent.my.model"></my-component>

And can instead write directives using isolate scope that behave as you would expect:

<my-component ng-model="my.model"></my-component>

Additional discussion: #1924 (comment)

[pkozlowski-opensource]

@IgorMinar @petebacondarwin I don't know how you feel about it but for me this it is more a work-around than a proper fix. It deals with the ngModel only but the problem mentioned in #1924 is more generic and present with other directives as well (eg. ngShow / ngHide).

@basarat This pull request is missing tests.

[basarat]

@pkozlowski-opensource I didn't realize the issue was with other directives as well (e.g. ngShow / ngHide). Further discussion in my comment: #1924 (comment) Feel free to close this request. I'll make an angular module that fixes ngModel for people that want to explicitly use it for now.

[pkozlowski-opensource]

@basarat OK, going to close this one for now.