Mismatch between program logic and user instruction for webserver verify task

We need to bring the user instructions for webserver access up to date so that they match up with the new logic in apps_installer_has_write_access().

That being said... i think it would be great, for many reasons, to install apps in either sites/all/modules/apps or perhaps even a new sites/all/apps. The former being much easier and the latter being probably an interesting idea for the future. Stricter permissioning would be the main functional reason for both suggestions however i also think if we really want to push forward the idea of apps as being distinct from core/contrib and higher up in the stack then we might want to consider something like the latter.

Anyways...