Update to Racket 6.1.1

Changes:

* The MAC OS X YOSEMITE compatibility problems are fixed. We
  bundled a patched Pango text-drawing library with Racket.

* The WINDOWS [32-bit] releases fixes the window-update crashes.
  We bundled a patched Cairo drawing library with Racket.

* TYPED RACKET closes two safety holes in the exception system.
  The revised type system restricts `raise' to send only
  instances of the `exn' structure type and flat data to
  handlers. It also checks exception handlers properly.
  NOTE: Previously well-typed programs may fail to typecheck.

* TYPED RACKET'S typed regions support casts and predicates.

* 2HTDP/IMAGE'S notion of equality ignores an image's baseline.

* The PACKAGE MANAGER supports a binary library installation mode,
  which allows users to install packages without source or
  documentation.  Use the `--binary-lib' option with `raco pkg
  install'.

* The new DRRACKET-TOOL-LIB package factors out parts of DrRacket's
  IDE so that they can be reused with other editors, such as Emacs.

* The COMPILER'S use-before-defined analysis has been repaired for
  certain forms of nested `letrec', some `let' forms, and some
  uses of `set!' or `with-continuation-mark'.

* The COMPILER performs additional bytecode optimizations.
  Thanks to Gustavo Massaccesi.

* The CML library comes with a new `replace-evt' event constructor.
  Thanks to Jan Dvorak.

* REDEX'S benchmark suite comes with a description of the benchmark
  programs.

* REDEX'S metafunctions can be typeset using the "large left brace"
  notation for conditionals.

* The CONTRACT library comes with an improved `contract-stronger?'.
  Its error messages note that the contract itself might be wrong.

* The GUI library is DPI-aware on Windows.

* The OPENSSL library supports Server Name Indication for servers.
  Thanks to Jay Kominek.

* The SYNTAX/PARSE library allows the definition of new pattern
  forms via pattern expanders, similar to match expanders.
  Thanks to Alex Knauth.

* OpenGL on Linux no longer depends on libgtkgl, and core profiles
  are supported (see `set-legacy?').

* The TEACHING LANGUAGES' unit test framework supports
  `check-satisfied', a construct for checking whether a result
  satisfies a predicate, e.g.: (check-satisfied (sort l) sorted?)

(asau)