in-terminal: add a `close-calllback` argument
GUI package manager: better strecthing mode for the DWIM panel
GUI package manager: remember selected DWIM file or directory
raco setup: use proper namespace for info-domain setup

With the wrong namespace, then installing and updating a package
within the GUI package manager would not pick up an info-domain
change for the updated package.
Make contract profiler's path shortening more robust.
fix problems with continuations & sharing

When continuation C2 extends continuation C1, C2 shares the copy
of the internal stack with C1. It needs to skip the bit of
C1's stack that corresponds to arguments to `call/cc`, though.
That skipping assumed that `call/cc` takes 1 argument, but it can
take 2. The bug broke `racklog`, which captures continuations using
its own prompt. (It seems like there should be a simple test that
is independent of Racklog, but I couldn't construct it.)

Meanwhile, the continuation shouldn't retain the arguments to
`call/cc`, so clear them. (That was easy to test.) Sharing still
has to compensate for the locations of the arguments, though.
fix bug in c53c29d9
adjust changes in 8027e48 so that we see intermediate
output during flushes instead of collecting the entire
contents of the buffer before flushing (at least in the
more common case)
mention the paper that this model comes from
Scribble manual: make "Images" section in ToC be useful

Remove the "Images" section for `scribble/manual`, add an "Images"
section for `scribble/base`.

As suggested by Shriram.
pkg/db: fix some missing table preparations
pkg/db: add support for grouping calls as a single transaction

Also avoids reundant table-preparation checks for calls that are
grouped together.
pkg catalog-update: install updates as a single transaction

Relevant to PR 14848
Add dummy file as part of DrDr transition in PR #833.
Install, build, and test specified pkgs in DrDr.

Initially just a test pkg, with a fixed source.