[plt-scheme] questions about profiling & DrScheme startup

1. Can the profiler be used in MzScheme, or is it only available
   inside DrScheme?

2. Is there a way to add to `current-library-collection-paths' when
   DrScheme starts up?  I don't like using the PLTCOLLECTS environment
   variable, because then I have to hard-code the system directory and
   the add-ons directory (which are only computed if PLTCOLLECTS is
   not set).

3. Is there a place to put arbitrary start-up code for DrScheme?
   MzScheme has .mzschemerc, and MrEd has .mredrc, but .drschemerc
   doesn't work.  I know about .plt-prefs.ss, but that seems to be
   auto-generated so I don't think I should be adding stuff to it.

--dougo at place.org