First Angular2 Prototype

[sphaso]

First prototype for an Angular2 version of the directive.
I've only manually tested the most basic case.

Problems and head-scratchers:

1. not sure how to handle "THROTTLE_MILLISECONDS", need to read more docs on ng2 as they become available
2. not sure how to handle "infiniteScrollListenForEvent" in a clean manner. I need to read more about how ng2 handles events and scoping
3. why do you need scope.$eval on infiniteScrollImmediateCheck?
4. the rationale behind the $watch-ers is that the bound value could change? (e.g. infiniteScrollDistance={someVarInControllerScope} ?)
5. there was a variable "context" in func throttle which wasn't used anywhere, hopefully I didn't miss anything
6. ng2 doesn't have an $interval service. My implementation of $interval(callback, delay, count) is a bit naive. I'd like to check the actual ng1 code
7. I'm not sure why you needed "angular.element"
8. Should the first PR take care of protractor \ tests \ build or can we think about it later once the codebase stabilizes?

[sroze]

Thank you for the effort you put on it @sphaso. Here are my answers:

1. You can do without it at the moment.
2. TBH, I don't remember
3. Yes, this is the idea
4. Yes, you can remove it.
5. This is to remove the dependency to jQuery
6. Definitely in my point of view. You can even remove the tests that are related to features you are not porting at the moment, but we need passing tests for all the claimed features :)

[sphaso]

@sroze sorry this is taking a bit long. My main dev machine was in bad shape and had to borrow another pc to run the tests. I have 33 on 33 green specs. I hope they're not false positives :)

[sphaso]

@sroze feel free to let me know if there's anything else you'd like me to do regarding this PR