fix(gridUtil): Allow multiple logDebug params

The function was previously only allowing one parameter. Now the args just
get passed straight on to $log.debug
fix(GridRenderContainer): Correct prevScroll*

prevScrollLeft and prevScrollTop were being set improperly in the
adjustScroll* methods. Neither were accounting for the viewport, causing
the value to be too large. Now it only sets the value if the scrollLeft or
scrollTop argument is not provided, and it includes the viewport in the
calculation.
WIP: Fixed horizontal scrolling