Add user profile tab label option in BP settings

Hi Boone-

I added the option for site admins to customize the label for the navigation tab in the user's profile. I also updated the group tab label to use the registered setting 'bp-docs-group-tab-name', but left in logic in case the old setting 'bp-docs-tab-name' is still in use.

The only commit of interest is: 3ea66554b474c

There's a bug I can't figure out: If you use a single quote in your label, WP will escape it. Save it again and the backslash gets escaped as well as the single quote. I'm using sanitize_text_field as the sanitization callback, so I'm not expecting this behavior. (I don't think sanitize_text_field is running. Slashes and ampersands get written to the database without being converted to entities.)

Also, git. If I haven't changed a single file and I merge from upstream, why does it think my local copy is more up-to-date than the upstream origin and cause conflicts everywhere? Is there a tutorial I should be reading? ;)

-David