Request: Allow dynamic changing of close direction

[Simon-Raes]

It would be nice to have an option to change the Slidr direction/position while in an Activity.

I currently use Slidr in an Activity with a RecyclerView. I detect the scroll events and enable/disable Slidr when necessary, but updating the closing direction (TOP when at the start of the list, BOTTOM when at the end) requires the creation of a new SlidrConfig and SlidrInterface.
This also does not work very well when using a ViewPager with multiple RecyclerViews.

I implemented a quick method of changing the direction here (Simon-Raes@6178de1), but there's probably a better way to achieve this.