Smaller top offset when autoscrolling the page after opening an entry.

The offset was a bit too big, two entries were visible above the currently open one (at viewport widths above the md- cutoff). This is too much screen space not dedicated to the currently open entry.

This change means that for viewport widths under the md- cutoff, only part of the previous entry is visible above the currently open one. I think it's a worthy tradeoff.
Added Velocity.js to the JS libraries used by the app.

It is supposed to implement an API almost identical to jquery.animate but with much better performance. See:

http://julian.com/research/velocity/
https://github.com/julianshapiro/velocity
Perform entry open/close animations with velocity.js, intead of jquery.animate
Animations with velocity.js use the single-object argument syntax, instead of three comma-separated arguments.

See http://julian.com/research/velocity/#arguments

This syntax enables us to specify options like "delay", which is not possible with the three-arguments syntax.
When opening an entry, the scrolling to show as much of its content as possible is performed with velocity.js.

Using Velocity.js "scroll" animation is supposed to have better performance and use hardware acceleration in mobile devices. See: http://julian.com/research/velocity/#scroll

The call to velocity("scroll") is chained to the call that animates opening the entry. It is supposed to give better performance this way, and it eliminates any timing problems (the scroll animation is guaranteed to start immediately when the open animation finishes).

This removes the need for a separate scrollSvc service. The ng-ScrollSvc.js.coffee file has been removed along with any references to scrollSvc.