add a test case to be sure recursive-contract accepts
values with sharing but without cycles
add a test for behavior that's not currently liked
add has-blame? and value-blame
bring back accidentally clobbered value-contract tests
distro-build: move a file out that is accessed directly

The "pack-all.rkt" file is needed before (and only before) the
distro-build package itself is ready, so move it to the "racket/src"
directory.
change default MSVC projects to Visual Studio 2010 (version 10) and up

Visual Studio 2008 is still supported by "9.sln" projects and
".vcproj" files, while ".sln" and ".vcxproj" work for 2010, 2012,
and 2013. The "build.bat" script detects which version of
Visual Studio is active and uses the appropriate ".sln" files.

The bad news is that we have two copies of each project until we
decide to drop support for Visual Studio 2008. (We had two copies
before, but one copy was unmaintained.) The good news is that
we have only 2 copies of each project, because recent versions of
Visual Studio are willing to use 2010 projects as-is.

Change project and related files to text instead of always CRLF,
because that seems to be ok for modern Windows tools.
fix `--enable-sgcdebug` build
fix glib build for Windows 64

The previous build attempted to cooperate with Valgrind in a way that
truncates a 64-bit address to a 32-bit address. Disable Valgrind
cooperation. (Other builds seem ok for now, but future rebuilds will
disable Valgrind cooperation for them, too.)
add note in syntax-parse docs about #:with and #:declare interaction
Fix occurrence typing when comparing Byte and Positive-Rationa.

Closes PR14568.
fix struct/dc's flatness test so that contracts with lazy fields aren't flat

closes PR 14558
add missing guard
Remove ability to check unreachable code.

If code is unreachable then looking up any variable should return
Bottom. But implementing checking unreachable code that way is not that
useful.
fixed indexing and typo; Closes PR 14575, Closes PR 14564
Add vars to tvar environment when infering poly function applications.
make installers: propagate SOURCE_MODE to clients
syntax-local-lift-...: fix for use during module visit

Closes PR 14573
INSTALL.txt: fix instructions for `make unix-style`
add keyboard shortcuts to unsaved dialog warning on mac os x

closes PR 12927
closes PR 10708
closes PR 8996
Windows build: use `msbuild` instead of `devenv` or `vsexpress`