Log Message:
Update rake to 0.8.7.

New features since 0.8.4:
* Improved implementation of the Rake system command for Windows.
  (patch from James M. Lawrence/quix)
* Support for Ruby 1.9\\\'s improved system command.  (patch from James
  M. Lawrence/quix)
* Rake now includes the configured extension when invoking an
  executable (Config::CONFIG[\\\'EXEEXT])