This is a prep commit for enabling a two section layout in the
buddy_list. The sections will be for "users" and "others".
Hence, this commit performs a simple rename of:
- `user_presence_row.hbs` -> `presence_row.hbs`
- `user_presence_rows.hbs` -> `presence_rows.hbs`
And then a search and replace of `user_presence_row` to
`presence_row` (which also handles the second rename).
It also makes one modification in buddy_list.js where it changes a
template variable we're passing from "users" to "row_members".
YashRE42