Audit usage of buddypress() and BP helper functions
Declare properties as public
Move template file to it's own folder

* Match BP's folder structure to make it a little more familiar
* Correct path in the display function so we can actually have a documents page
Remove BP 1.1 code

BP Group Documents won't load, and hasn't for quite some time, on 1.1 installs. Let's remove the unneccessary cruft. No core functionality should be changed, just removing bandaid code to make 1.1 installs return the same results as newer installs.