Installer admin rights (#358)

The installer of software ideas requires admin rights.

If a user doesn't have admin rights or cancels user account control the installer can still continue with installation but then the user has to choose a other folder where it has writing rights to instead of program files.

If this is not implemented I think it is nice to include information about needing admin rights on the download page and inform the user when the installer is aborted when running without admin rights.