Removed CreateUninstallRegKey portable mode example as discussed in #37.
Added new command line parameter supported by Inno Setup's own installer: /PORTABLE=1. Causes Inno Setup's own installer to not create an uninstaller nor an entry in the Add/Remove Programs Control Panel applet. Also supported by QuickStart Pack's installer.

Asked Tim Chilvers of Inno Script Studio to add it to his installer well so that QuickStart Pack can pass it on.

Closes #37.