update rake tasks
Use two parameter form of #system to avoid setting environment variables on the command line

* Partially reverts d02a01711c9b4e8fb5e402fc832d29bcc7a95e02
* Avoids setting environment variables as a command prefix which is not supported by the Windows command processor
Use Process.kill instead of system("kill...")

* The version of kill.exe (v 1.14 cygwin) distributed with git for windows (v 1.8.1.msysgit.1) fails on Windows. Using Process.kill works fine.
Merge pull request #10 from cablegram/windows-fix-kill-process

Use Process.kill instead of system("kill...")
Merge pull request #9 from cablegram/windows-fix-setting-env-vars

Use two parameter form of #system to avoid setting environment variables...
deprecated 1.8.7
Version bump to 0.4.5