move planet test specifications into the test files and out of info.rkt

and also minor rackety
whoops: remove duplicate test submodule
raco test: responsible-party and varying-party logging, lock names

The responsible party for a test defaults to the enclosing package's
author.

Also, add support for a `test-timeouts` fallback in "info.rkt".
copy `responsible` info to "info.rkt" files

It seems more ideal that `pkg-authors` would be specific enough
responsibility, but our existing allocations of responsibility are
more fine-grained, and we keep them for now.
copy `gracket` command props to `lock-name` as "gui" test config
copy `drdr:random` command props to test configs
the planet tests should not count as random
allow looking at a pkg lockfile in the sandbox

(this comes up when building <pkgs>/ paths, something the
contract system does)
racket/gui cocoa: preserve resolution of bitmaps as control labels

This change is mainly for Retina display mode.
racket/draw: add a backing-scale argument to bitmap constructors

Generalizes backing-scale support created for `make-platform-bitmap`
and Mac OS X in Retina mode so that any bitmap can be created with
a backing scale (except monochrome bitmaps or bitmaps with masks).
images/icons: add `backing-scale` arguments

By default, icons render with a backing scale of 2.
racket/draw: add `#:try-@2x?` argument to `read-bitmap`
DrRacket: enable @2x bitmaps for tool icons
some @2x tool icons
racket-style.css: move margin-note img formatting to Guide/Ref icon

Setting image with to 1.5em seems to be aimed specifically at
the cross-reference icons in the Guide and Reference, and the
width should not apply to just any image in a margin note.
Removed recently broken "doc-tests.rkt"

The breakage was from `declare-exporting' now requiring at least one
module path. Plot's docs build makes the test superfluous, anyway.
Racket splash/about logo @2x
Dienprogramm logo @2x
if a bitmap has a non-1 backing scale, always draw smoothly to other contexts
Make tc-setup just take a function instead of 3 identifiers.