fixes distance from scroll

[jakeleboeuf]

This PR uses @caltabid's suggested fix to address issue #38.

[sardyy]

@Duder-onomy Hello! Can you check this pull request and launch a new release? It fixes some problems I'm facing right now.

[Duder-onomy]

I just took a look and this seems reasonable to me, anything that can be done to simplify the get the elements top logic is good. Considering people claim that this is fixing something, can you manage to write a failing test? If not, why do the current tests pass when they are broken in your implementation? The app I work on uses this allot, this page for example uses the lib to power those ['overview', 'details', 'location', 'reviews'] tabs, they work fine when scrolling in reverse (which I believe was the original issue in #38)

Anyways, I just pulled this in and ran the test suite on the decently massive ember app I work on and things look good.

However, @sardyy I cannot merge things here. I don't have those permissions.

------------ UPDATE -------------

I can confirm that 0.6.4 is broken, but 0.6.5 work fine for me, #37 fixed this issue for me, but we need to get 0.6.5 out.
@ragnarpeterson #40 needs to happen. Then I think this PR can be closed.

[sardyy]

Hey @Duder-onomy.

First of all, thank you for your reply.

Yeah, you are right. I wrote this comment before testing the addon using the master branch and it's actually working, so this PR doesn't fix anything related to my problem because it was already fixed with 0.6.5.