fix(dropdownToggle): use $animate for adding and removing classes

[olostan]

As AngularJS 1.2 was released, there is a need to use $animate for adding and removing classes.

[olostan]

I was not able to run tests as misc/test-lib contained Angular 1.0.8 and after updating to 1.2 I got about 90 failed tests in other components.

[pkozlowski-opensource]

@olostan what would be the immediate benefit? We want to move to $animate but at present is still in a bit of flux and has some bugs to be fixed, so I'm not too keen to jumping on it immediately.

What is your primary motivation here?

[olostan]

@pkozlowski-opensource My use case is adding some animations to dropdown when it is toggled.

Here is a stripped (so little bit ugly) code from real project: http://plnkr.co/edit/NWYCpczUwhGwVPr71D2M?p=preview

Without this tiny patch ( jqLite.addClass -> $animate.addClass) gives a possibility to do such kind of animations.

[bekos]

@olostan Can you rebase on the current master? If it is to much trouble you can always create a new PR.
@chrisirhc I assign this to you since you are the animations master :-) BTW if this is going to be merged it would be nice to somehow have it also in our demo page.

[olostan]

Created another pull request: #1644