title: element scrollTo in controller or directive in AngularJS?
body: <p>I'm just learning Angular, so apologies if this is a noob question.
  I'm trying to create a fixed position sidebar that will contain buttons(or links) that will scroll to different elements on the page. So my first thought is the button click should attempt the scrollTo, but supposedly this is not the Angular way, all DOM mods should be done in a directive.
  The best example I could find is here:
  <a href="http://plnkr.co/edit/Po37JFeP5IsNoz5ZycFs?p=preview" rel="nofollow">http://plnkr.co/edit/Po37JFeP5IsNoz5ZycFs?p=preview</a></p>
  
  <p>This example places a directive on the elements being scrolled to and the links that kick off the scrolling just have # hrefs. While I get what's happening, I don't understand how adding the directive to the element actually works (in this case the h3). Does the directive watch the location element and when that changes, this is how the directive is executed?</p>
  
  <p>The $anchorScroll pattern will not work for me as I have a fixed header in place and need to scroll to the element in question with a negative offset to account for the header. From what I have read about the project, this is a known issue and a fix is in the works.</p>