[ESS-bugs] Makeconf suggestion for Aquamacs

[Dan Knoepfle]

You might save a bunch of easily-confused Mac users some time by
adding an Aquamacs section to Makeconf, like

## Aquamacs
#DESTDIR=/Applications/Aquamacs.app/Contents/Resources/lisp/aquamacs/edit-modes
#PREFIX=$(DESTDIR)
#EMACS=/Applications/Aquamacs.app/Contents/MacOS/Aquamacs
#LISPDIR=$(PREFIX)/ess-mode/lisp
#INFODIR=$(PREFIX)/info
#ETCDIR=$(PREFIX)/ess-mode/etc

Thanks for all the great work on ESS,
Dan