Change Windows installer directory - fixes #17

[ghost]

• windows/portmaster-installer.nsi: The big change:
  • Set the InstallDir to %Programdata%\Safing\Portmaster - tricky since it has to be set at runtime.
  • Place a Symlink @$Programfiles64\Safing\Portmaster.lnk.
  • Make an Update-Routine for Installations using the old installer (copying from the old uninstall-routine).
  • Uninstall everything (except db&logs) on Uninstall.
• windows/install_summary.rtf: Changed what is installed where. Feel free to change working.

Small changes:

• The .gitignore Windows-Part didn't work for me, so I replaced it with a simple *.exe. There shouldn't be a binary blob in an automated build source anyway.
• Makefile: add install_summary.rtf as requirement for install_summary.nsh so it gets rebuilt automatically
• windows/portmaster-installer.nsi: Fixed Intention
• windows/portmaster-installer.nsi: rename jump-label noupdate to dontUpdate for less missunderstanding (is it?)

[ghost]

Don't stress yourself. But since I don't want to do a "deploy on last day of internship", a review would be great if you want me to fix things in this branch before leaving.