Change vjs.findPosX to vjs.findPosition to return both left and top.
This also removes the fallback method that doesn't use the
getBoundingClientRect because according to MDN[1] and PPK[2], it should
be supported just about everywhere.

[1] https://developer.mozilla.org/en-US/docs/DOM/element.getBoundingClientRect#Browser_compatibility
[2] http://www.quirksmode.org/dom/w3c_cssom.html#documentview
Make sliders able to handle vertical sliders in calculateDistance.
This takes a 'vertical' option on the slider bar itself. If set, it will
use the top and pageY values to calculate the slider positions.
Make sure to return an object if box doesn't exist
Null check gBCR
Add a few tests for vjs.findPosition
fix jshint errors
Merge pull request #477 from gkatsev/verticalSlider

Vertical slider