term: Move DISABLE_AUTO_TITLE check to hooks
term: Move DISABLE_AUTO_TITLE check to hooks

Move the DISABLE_AUTO_TITLE check from title() to the preX hook
functions that call it, to allow the title() function to be used
directly by user or other callers.

cabbiepete/oh-my-zsh,cabbiepete/oh-my-zsh,cabbiepete/oh-my-zsh,cabbiepete/oh-my-zsh