[O] sort habits by priority

[Jesse Johnson]

I want to sort habits by priority, such that priority overrides all 
other criteria (schedule, deadline, consistency, etc.).

In attempting to implement this I discovered that org-habit-get-priority 
is an inline function and thus cannot be overridden by the user. There 
seems to be no straightforward way to accomplish my goal without editing 
the org source code directly.

I am not the only one to run into this problem: 
http://stackoverflow.com/questions/37200762/sort-todays-habits-by-priority-in-main-agenda-view

I think the best solution is either to make org-habit-get-priority a 
regular function (assuming this doesn't cause a serious performance 
degradation) or to add user-customizable variable(s) which can configure 
how habits are prioritized.

Thoughts?

Jesse