New Racket version 5.3.5.1.
reorganize into core plus packages

The "racket" directory contains a pared-back version of the
repository, roughly.

The "pkgs" directory everything else in the repository, but
organized into packages.
fix for `find-relevant-directory-records'

Multiple package-based instances of the same collection were not
handled correctly.
win32: fix version info in executables

Also, remove the need for a cron job that patches the version
number in resource and manifest files.
move recently added file
raco setup: fix some info-dmain problems

Info for "lib/collects" collections could be put in the wrong place,
and `--tidy' mode could miss some caches.
unbreak keybinding file removal

(the pkg library shadows the list function 'remove' which
broke the callback for removing a keybindings file)
adjust various drracket keybindings so they are not just "m:"
but are now "~c:m:" to try to ward off alt-gr related problems
under windows
fix 77a4a8c2766f2d5648e100ff237fd69dd4abccfd

related to PR 13863
move the framework tests into the gui package
update framework tests to reflect new location
fix an infinite loop in find-next-outer-paren

closes PR 13863
move framework tests to their own package (but still inside the framework collection)
adjust games to use find-relevant-directories instead of
working directly with collections

also some Rackety
Fix the filename of the Ubuntu build.

The actual file *is* an x86_64 build.
win32: fix `win32-in-place' target on existing tree
paint-by-numbers: fix path construction

Syntaxes of filesystem paths and module paths are not the same
under Windows.
mzcom: fix installer
mzcom: set mzobj interface version to bogus value, for now

MzCOM and its build process need some sort of overhaul, but
it's on the backburner for now.
raco setup: better tracking of provides in database

Keep track of the out<n>.sxref timestamps, so that `raco setup'
can detect when the database is out of sync (instead of assuming that
it's always in sync with out<n>.sxref files).